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The effects of metal/non-metal ratio (M/NM ​= ​ x : 1) on the microstructure and magnetocaloric properties of promising melt-extracted Mn–Fe–P–Si microwires with short heat treatment have been investigated here. More Fe 2 P principal phase, which is considered favorite for magnetocaloric effect (MCE), should achieve at low M/NM ratio and the fraction of Fe 2 P phase increased with the reduction of x. Meanwhile, the (Mn, Fe) 3 Si impurity phase is formed for x ​= ​2.00–1.90 whereas change to (Mn, Fe) 5 Si 3 structure for x ​= ​1.85. It's worth noting that a metal deficiency resulted in the thermal hysteresis (T hys) and the magnetic hysteresis loss (W y) decreased by ∼40 ​%., The magnetic transition temperature (T tran), peak value of isothermal magnetic entropy change (− Δ S iso peak), refrigerant capacity (RC) and effective refrigerant capacity (RCE) first increased then decreased with the decrease of x , and reached the maximums at x ​= ​1.90, i.e., 370 ​K, 26.0 ​J ​kg−1 ​K−1, 367.4 and 339.8 ​J ​kg−1, respectively. Therefore, the customizable microstructure and magnetic properties of the melt-extracted (MnFe) x (P 0.5 Si 0.5) microwires will be achievable effectively by tuning M/NM ratio x , and optimized Mn–Fe–P–Si compounds with novel thermomagnetic properties will be obtained. [Display omitted] • The (MnFe) x (P 0.5 Si 0.5) microwires were fabricated by melt-extracted method. • The high amount of Fe 2 P phase would be obtained by reducing the M/NM. • The ​− ​ Δ S iso peak is −26.0 ​J ​kg−1 ​K−1 (5 ​T) for the wires with x ​= ​1.90. [ABSTRACT FROM AUTHOR]

Solid-state magnetic refrigeration, based on the magnetocaloric effect, is a promising, highly energy-efficient, and environmentally friendly cooling technology. High-entropy metallic glasses (HE-MGs) have attracted increasing interests due to their excellent magneto-caloric properties across a wide temperature range. In this work, we successfully prepared three rare-earth (RE) based HE-MGs microwires and investigated their structural and magnetocaloric properties. The Gd 25 Dy 25 Co 25 Al 25 , Tb 20 Gd 20 Dy 20 Co 20 Al 20 , and Ho 20 Gd 20 Dy 20 Co 20 Al 20 microwires exhibit an amorphous structure with good glass forming ability. They undergo a second-order phase transition from ferromagnetic to paramagnetic states around Curie temperatures of ∼61 K, ∼63 K, and ∼ 47 K, respectively. The peak magnetic entropy change (-Δ S M) for these HE-MGs microwires range from 8.2 J kg−1 K−1 to 10.2 J kg−1 K−1 under a 5 T magnetic field change. Furthermore, the refrigeration capacities of these microwires are evaluated to be between 504 J kg−1 and 507 J kg−1 (5 T), demonstrating their exceptional cooling efficiency. Additionally, this study provides valuable insights for the further research and development of RE-containing HE-MGs, paying the way for optimized materials tailored for advanced magnetic refrigeration applications. [Display omitted] • GdDyCoAl-based high-entropy metallic glass microwires were fabricated successfully. • Maximum magnetic entropy changes 8.2–10.2 J kg−1 K−1 for 5 T were reached. • A second-order phase transition from ferromagnetic to paramagnetic state was obtained. • Refrigeration capacities 504 J kg−1-507 J kg−1 for 5 T were achieved. [ABSTRACT FROM AUTHOR]

[Display omitted] • Partial amorphization under 120 ns laser impulse observed in DyPrFeCoB microwires. • The amorphized layer exhibits an almost periodic radial domain structure. • Laser impulse restores initially amorphous state disappeared under thermal annealing. • Laser causes surface amorphization at a depth of ∼1 µm. • The surface amorphous layer protects MEMS microdevices from aggressive environments. Magnetic microcombs are necessary in microrobotics, MEMS technologies, actuator and magnetic flow analyzer industries. Usually, magnetic microcombs are artificial linear magnets of periodic shape. We propose another type of microcombs based of microwires, where periodicity of magnetization is caused by equidistant alternation of natural domains. We have demonstrated the presence of quasi-periodic radial magnetization and the effect of temperature and magnetic field on magnetic relief in PrDyFeCoB microwires. Accurate analysis of chemical, phase and structural composition of the microwires allowed us to reveal necessary conditions for the creation of periodical magnetic relief. Annealing affects magnetic relief and changes structure of initially amorphous microwires. Crystal structure of inclusions enriched with Fe and Co instead of Dy and Pr is body-centered cubic (BCC), while the bulk of the microwire has tetragonal structure. We have found laser stimulated amorphization of surface of PrDy-FeCo-B microwires. Partial restoration of the amorphous structure in polycrystalline microwires under single laser pulse of irradiation of 1mJ power and 120 ns duration has been found in 1–2 μm depth. [ABSTRACT FROM AUTHOR]

GaN nano- and microwires have gained increasing interest due to their unique geometry and flexibility, and have already been successfully applied in optoelectronics. One important advantage is their superior crystalline quality in comparison to their thin-film counterparts. Beside this, GaN is also known for its high radiation hardness, owed to the large displacement energy of the atoms in its crystal lattice and efficient dynamic annealing properties. In this work, single GaN core–shell p–n junction microwires have been processed into radiation detectors and the induced damage effects on the electrical and optoelectrical characteristics, when irradiating the detectors with 1 and 2 MeV protons, have been studied. By measuring the dark and photocurrent as a function of the irradiation fluence we show that for fluences up to 1 × 1 0 14 protons/cm2 there is no significant modification of any of the parameters and that serious degradation only occurs for fluences above 1 × 1 0 15 protons/cm2. Furthermore, we also observe that the dark current decays at a lower irradiation fluence with respect to the photocurrent due to the different impact of the created irradiation defects on the properties of the neutral region and the p–n junction. As a consequence, the signal-to-noise ratio of the detector is strongly enhanced, especially when applying a higher reverse bias. Thermal treatments furthermore show that the degree of recovery of the properties of the detectors is strongly dependent on the irradiation fluence. The detector irradiated with a fluence of 5 × 1 0 14 protons/cm2 almost completely retrieved its pre-irradiation characteristics whereas the detector irradiated with 5 × 1 0 15 protons/cm2 only showed a minimal recovery. • Properties of the microwires are not modified up to a fluence of 1 × 1014 protons/cm2. • For a fluence of 1 × 1015 protons/cm2 the properties are more severely affected. • The dark current decays at a lower fluence than the iono- and photocurrent. • A strong enhancement of the signal-to-noise ratio is observed. • Samples irradiated with lower fluence show very good recovery of their properties. [ABSTRACT FROM AUTHOR]

An inhomogeneous elastocaloric effect has been found and investigated in the present Cu–Al–Mn shape memory microwires by using the combined technique of infrared thermography and electron backscatter diffraction. Upon unloading, a reversible temperature change of ~5 K has been detected within the 5 mm gauge length. Inhomogeneous temperature distribution can be directly observed on the surface of microwires through infrared thermography measurement. Different regions of the microwires, involving bi-crystalline, oligo-crystalline, single-crystalline and poly-crystalline grain architectures, display different eCE cyclic stability, which can be ascribed to the heterogeneous grain architectures, the discrepancy of grain orientation and the varied neighboring grain constraints. Image, graphical abstract [ABSTRACT FROM AUTHOR]

• Cylindrical shape of sample is responsible for peculiar magneto-optical contrast. • Surface shape of a magnetic domain wall in microwire is studied by two detectors. • The domain wall has an inclined shape with strong surface distortions. Thin magnetic cylinders are in focus of interest due to peculiar features of domain wall motion like absence of the Walker breakdown. Here, we propose an experimental technique based on magneto-optical Kerr effect that allows surface studies of a domain wall shape in thin microwires. Our setup is optimized for characteristic optical and magneto-optical features of thin magnetic cylinders. Time-resolved measurements of a magnetic contrast along the circumference of wire are used to reconstruct a three-dimensional image of a surface domain wall shape. Our measurements confirmed a tilted shape of domain wall, in agreement with previous observations of microwires with positive magnetostriction alloy. The experimental technique represents a new way for direct visualizations of a surface magnetism of thin cylinders in optical range. [ABSTRACT FROM AUTHOR]

Abstract In this paper, a systematic growth behavior of Cu, Ni and Cu/Ni microwire arrays in porous silicon (PSi) templates is presented. After preparation of PSi templates via anodizing in HF solution, such microwires are successfully grown into PSi templates by electrodeposition method. Systematic scanning electron microscopy (SEM) imaging reveals that Cu seed nucleation occurs at the bottom and Ni seed nucleation starts on the wall of the silicon pores. The different growth models are explained according to the observed diffusion coefficients of ionic elements in electrodeposition baths. X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDX) were used to further observe the structural characteristics of the grown microwires. We believe that this work can be used in developing microwires with desired structural characteristics. Highlights • Deposition of Cu, Ni, and Cu/Ni microwires within porous Si was investigated • Nucleation of Cu seed occurred at the bottom of silicone pores • Nucleation of Ni seed started on the wall of silicone pores [ABSTRACT FROM AUTHOR]

Abstract Detection of viral infection is commonly performed using serological techniques like the enzyme-linked immunosorbent assay (ELISA) to detect antibody responses. Such assays may also be used to determine the infection phase based on isotype prevalence. However, ELISAs demonstrate limited sensitivity and are difficult to perform at the point of care. Here, we present a novel technique for label-free, rapid detection of ultra-low concentrations of virus specific antibodies. We have developed a simple, robust capacitive biosensor using microwires coated with Zika or Chikungunya virus envelope antigen. With little discernable nonspecific binding, the sensor can detect as few as 10 antibody molecules in a small volume (10 molecules/30 µL) within minutes. It can also be used to rapidly, specifically, and accurately determine the isotype of antigen-specific antibodies. Finally, we demonstrate that anti-Zika virus antibody can be sensitively and specifically detected in dilute mouse serum and can be isotyped using the sensor. Overall, our findings suggest that our microwire sensor platform has the potential to be used as a reliable, sensitive, and inexpensive diagnostic tool to detect immune responses at the point of care. Highlights • A capacitance sensing system was developed that can detect as few as 10 anti-Zika or anti-Chikungunya virus specific monoclonal antibodies with almost no cross-reactivity. • The system accurately determined the isotype of antibodies targeting Zika or Chikungunya virus antigen. • The system could to detect Zika virus specific antibodies in immunized mouse serum as few as 4-days post-immunization. • This system has the potential to be developed into a simple yet robust diagnostic platform for pathogen antibody detection and isotype determination. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • One-dimensional Ni microwires were synthesized by two-step MFI method. • Ni particles turned from nanospheres to microwires for magnetic field. • Brownian motion and magnetic moments affected the morphology of Ni microwires. • The length increased with magnetic field, while the diameter decreased. • The magnetic field improved the spontaneous magnetization of Ni microwires. Abstract One-dimensional nickel (Ni) microwires were synthesized by the magnetic-field-induced (MFI) microemulsion-hydrothermal method using Ni nanospheres as seeds. The influence of the chemical conditions and magnetic field on the morphology and magnetic properties of Ni microwires were investigated by X-Ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The strength of magnetic field greatly affected the morphology and magnetic properties of Ni microwires. The growth and morphology of Ni microwires depended on the competition between Brownian motion and magnetic dipole moments from magnetic field. The larger nanoparticles with the higher magnetic moments preferred to form one-dimensional Ni microwires and their length increased up to several millimeters with the increasing magnetic field strength, while the average diameter of Ni microwires decreased. Furthermore, the easy magnetization direction of Ni microwires was parallel to the direction of magnetic field and the Ni microwires axis. [ABSTRACT FROM AUTHOR]

The large-scale ZnO microwires (MWs) arrays with different Sb doping concentrations were grown by chemical vapor deposition method without using metal catalyst or seed layer. The diameter and length of MWs were about 20–50 μm and 1–2.5 cm, respectively. The experimental results indicated that the length and orientation of ZnO MWs were improved gradually with increasing Sb concentration. The surfactant effect of Sb should be the major improvement reason. Furthermore, thermoelectric microgenerators based on single Sb doped ZnO MW have been fabricated on a glass substrate, which can generated maximum output voltage of 68 mV and maximum output current of 782 nA under a temperature difference of 20 K between the two electrodes. The single Sb doped ZnO MW showed a Seebeck coefficient of about 3.4 mV/K. In addition, the output current of the device was increased dramatically in ultraviolet (UV) illumination compared to dark conditions. The detail of the UV irradiation enhanced output properties of microgenerator was also discussed. [ABSTRACT FROM AUTHOR]

A novel impedimetric biosensor was developed for the detection of the two extensively used pesticides, acetamiprid and atrazine. By employing the sputtering and e-beam lithography techniques, platinum nanoparticles (Pt NPs) were deposited in a bridge-like arrangement, in between interdigitated electrodes (IDEs). The resulting Pt NP microwires were chemically functionalized to allow the covalent immobilization of aptamers against the two target analytes onto the sensor surfaces. The biosensing platform facilitated charge transfer through the microwire-bridged IDEs, while upon analyte binding to the immobilized aptamers electron transfer was hindered, resulting in an increase of the electrochemical cell's impedance. The combination of Pt NPs microwires and aptamers allowed the sensitive and highly selective detection of acetamiprid with a linear range of response in the range of 10 pM to 100 nM with a limit of detection (LoD) at 1 pM, and of atrazine with a linear range of responses from 100 pM to 1 μM and a LoD at 10 pM respectively. Its performance was tested against a number of other commonly used pesticides as well as in real water samples. [ABSTRACT FROM AUTHOR]

The investigation addresses the role of Al in devitrification stage of a series of (Co 94 Fe 6) 72.5 Si 12.5−x Al x B 13 Cr 2 (X = 0, 2, 4, 6 at%) rapidly quenched microwires. The incorporation of Al displayed reduction in primary onset and activation energy (A.E) while it facilitated widening of span between primary and secondary crystallization onsets. The Giant Magneto-Impedance (GMI) behaviour was influenced by Al concentration as well as applied uniaxial stress. Optimal Al containing alloy (x ∼ 2 at%) displayed signature of asymmetric dual peak at the operating frequency of 1 MHz and its prospective application as a very low magnetic field sensor in pre-stressed condition. However, with increasing stress, the asymmetric character transformed to symmetric dual peak which is attributed to the transition of transverse anisotropy to circular anisotropy via helical anisotropy. High stress sensitivity has been attributed to either dominant transverse or circular anisotropy. The transition of stress induced anisotropies in the microwires has been portrayed schematically to elucidate the transitions. • The Al incorporation for Si impacts on magnetostriction and anisotropy of microwires. • The microwires reveal change in GMI peak shape with applied stress. • The change in shape of GMI peak (dual, single) with uniaxial stress is associated to change in anisotropy. • Transition in helical, circumferential and transverse anisotropy with stress and compositional is discussed. [ABSTRACT FROM AUTHOR]

Localized electrodeposition is an additive manufacturing method for fabricating three-dimensional microstructures with precise control over process conditions and geometry of deposit. This technique has been widely used in the last two decades, because it makes possible to form various types of microstructures using no complex and expensive equipment. The rate of deposit growth, its dimensions and morphology depend on a large number of factors. A discrepancy between the deposit growth rate and the velocity of moving anode is of critical importance: if the deposition rate is higher than the anode velocity, the interelectrode gap decreases up to a short circuit; if the deposition rate is lower than the anode velocity, the interelectrode gap increases, the deposit ceases to grow, and, eventually, it becomes impossible to obtain a microstructure with a high aspect ratio. Along with the anode velocity, the interelectrode gap also has a strong effect on the deposit shape and dimensions. In several works, it was shown that different structures, such as microwires and microtubes, can be formed. However, the regularities of the process have not been adequately studied. This work is devoted to the simulation of localized electrodeposition with moving ring-shaped microanode. The Laplace equation for the potential in the solution and the equation for cathode surface evolution are used as the mathematic model. The kinetics of electrode reaction of metal deposition is taken into consideration by the Butler-Volmer equation. To provide the production of microwires and microtubes with a high aspect ratio, the anode rate was taken to be equal to the highest local rate of deposit growth. The effect of process parameters and microanode geometry on the deposit shape and dimensions is theoretically studied. [ABSTRACT FROM AUTHOR]

Ultra-long Zn 2 SnO 4 -ZnO microwires were synthesized by thermal evaporation of the mixture of SnO 2 , ZnO and C powders. Microstructural characterization by means of X-ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy showed that Zn 2 SnO 4 -ZnO microwires with excellent crystallinity were 2.8–3.2 μm in diameter and 4.0–4.2 mm in length. The maximal length-to-diameter ratio of Zn 2 SnO 4 -ZnO microwires is approximately 1500. H 2 sensing properties showed that Zn 2 SnO 4 -ZnO microwires exhibited not only excellent reversibility to H 2 , but also a good linear relationship between the sensor response and H 2 concentration. The response time and recovery time decreased as the operating temperature increased. The highest sensor response of 9.6 to 1000 ppm H 2 was achieved at an operating temperature of 300 °C. The electron depletion theory was used for explaining H 2 sensing mechanism by the chemical adsorption and reaction of H 2 molecules on the surface of Zn 2 SnO 4 -ZnO microwires. [ABSTRACT FROM AUTHOR]

The aluminum nitride (AlN) one-dimensional microwires (UWs) are promising candidates for the achievement of highly efficient optoelectronic devices. Here, we report the successful synthetization of large-scale nonpolar AlN UWs without any catalysts using physical vapor transport (PVT). The growth direction of high-quality UWs is along m-orientation. The morphology of AlN UWs was examined by scanning electron microscopy (SEM), and they show a rectangular cross-section with a polyhedral tip. The tip of UW undergoes four morphological evolution driven by growth kinetics and free surface energy minimization. The unique cathodoluminescence (CL) patterns were found in the UW. Both sides of UW exhibit strong violet luminescence (345 nm). In contrast, other violet luminescence (320 nm) and blue luminescence (450 nm) were observed in the center of the UW. The evolution of the morphology of UW crystal suggests that the defect-related luminescence pattern may be related to the difference in impurity incorporation efficiency on a- and m-crystalline planes. The photoluminescence (PL) spectra were obtained and the Fabry–P é rot cavity mode in the microwire was demonstrated. The emission anisotropy of AlN may also contribute to the CL luminescence pattern of the microwires. • The high-quality nonpolar aluminum nitride microwires with rectangular cross-sections and a polyhedral tip were synthesized by the PVT. • The alternating a- and m-crystalline planes exist at the tip as microwires grow. • A direct correlation between the unique "sandwich structure" cathodoluminescence patterns and the non-uniform distribution of impurity perpendicular to the UW growth axis was established by energy dispersive X-ray spectroscopy • The difference in impurity incorporation efficiency on a- and m-crystalline planes is responsible for the local enrichment of impurities. [ABSTRACT FROM AUTHOR]

Small-sized materials with large surface to volume ratio favor heat transfer during magnetic refrigeration cycling and thus may help enhancing the refrigeration efficiency. Here, high Fe content Ni 44.9 Fe 4.3 Mn 38.3 Sn 12.5 polycrystalline microwires were prepared by a melt-extraction technique. The as-extracted microwires were annealed at 1173 K for 60 min, leading to significant grain growth and formation of a secondary Fe-rich γ phase. The annealed microwire exhibits larger magnetization difference ( ΔM ) between the austenite and martensite phases and smaller thermal hysteresis compared to the as-extracted microwire. The annealed microwire possesses a magnetic transition to austenite at 299 K, followed by a martensitic transformation (MT) from a ferromagnetic austenite to a weak-magnetic martensite at 208 K upon cooling. Under a magnetic field of 50 kOe, the annealed microwires show a maximum magnetic entropy change ΔS m of 6.9 J/kg·K and an effective refrigeration capacity RC eff of 78.0 J/kg over a broad working temperature span ΔT FWHM of 20 K around the MT. In addition, magnetic transition of the austenite gives rise to ΔS m − 3.7 J/kg·K and RC mag 232.5 J/kg with ΔT FWHM of 85 K under 50 kOe. [ABSTRACT FROM AUTHOR]

In this article the results on the detailed investigation of the structural, elastic and magnetic properties of the “thick” Fe 73,5 Si 13,5 B 9 Nb 3 Cu 1 and Fe 31 Co 34 Ni 10 (SiB) 25 amorphous microwires with the glass shell, produced by the modernized Ulitovsky–Tailor method, are presented. The diameter of the metallic core of microwires was varied from 50 to 200 µm. It was found that the core has the stable geometric parameters along the microwire length and the smooth (almost without defects) surface. The studied samples are characterized by the weak dispersion of magnetic anisotropy of the near-surface layers and the high homogeneity of the near-surface local magnetic properties. Furthermore, the microwires exhibit the high plasticity and strength. They are not destroyed even after their full tightening into a knot. The strong influence of tensile stress and torsion on the magnetic properties of the microwires was discovered. The comparison of magneto-field behavior of the studied samples was performed. [ABSTRACT FROM AUTHOR]

A room temperature ethanol sensor based on Au-modified zinc oxide microwires (Au/ZnO MWs) is demonstrated. Au nanoparticles (Au NPs) were immobilized via ion sputtering onto the surface of CVD-fabricated ZnO microwires (ZnO MWs) to serve as sensitizers. Au modification was characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and photoluminescence. Gas-sensing tests indicated that the modified microwires exhibited an enhanced performance relative to the unmodified ZnO microwires over a wide gas concentration range, with very stable repeatability, fast recovery time and high sensing response and selectivity. A sensing mechanism is described in terms of localized surface plasmon resonance (LSPR) effect of Au NPs. The superior sensing characteristics indicate the device's potential applications as room-temperature gas sensor, and a straightforward and economical fabrication also makes it very attractive for more widespread use. [ABSTRACT FROM AUTHOR]

The aim of this work is to present a complex experimental and theoretical study of the ferromagnetic resonance frequencies and plasma behavior for CoFe-based, Co-based, Fe-based and FINEMET TM glass covered amorphous microwires (GCAWs), arranged in parallel configurations as free-standing systems, as well as combinations thereof, in order to obtain metastructures with tailored and enlarged left-handed frequency domain. The negative magnetic properties interval of the metastructures is expanded by alternating different types of GCAWs with close natural ferromagnetic resonance (NFMR) and natural antiferromagnetic resonance (NFMAR) domains, respectively. [ABSTRACT FROM AUTHOR]

Zinc germanate (Zn 2 GeO 4 ) microrods have been grown by a catalyst free thermal evaporation-deposition method. The microrods, with lengths of up to hundreds of microns have hexagonal cross section and faceted tips with morphologies in agreement with the rombohedral crystal structure of the germanate. Photoluminescence (PL) of the structures shows a broad band centered at about 2.4 eV, which is found by Gaussian deconvolution to consist of three components. A luminescence band at higher energies, centered at about 3.45 eV, is revealed by excitation with 20 kV electrons in the scanning electron microscope (SEM) or by PL under high excitation conditions. Resonance peaks observed in the luminescence spectra have been interpreted by the formation of Fabry–Perot modes in the hexagonal cross section of the rods. The waveguiding behavior of the rods has been assessed by excitation with a 325 nm laser and by detection of the excited luminescence emission transmitted along the rod. Micro Raman spectra of the rods show four bands in the range 740 cm −1 –820 cm −1 , with the most intense one peaked at 801 cm −1 . Comparison with Raman spectra of GeO 2 and of other germanates suggests that this set of bands, characteristic of Zn 2 GeO 4 is related to vibrations of Ge–O bonds. [ABSTRACT FROM AUTHOR]

Tensile experiments on cold-drawn Ni microwires with diameters from ~115 to 50 µm revealed high strengths, with significant strength variability for finer wires with diameters less than ~50 µm. The wires showed pronounced necking at fracture. The coarser wires with diameters >50 µm exhibited conventional ductile cup-cone fracture, with dimples in the central zone and peripheral shear lips, whereas finer wires failed by shear with knife or chisel-edge fractures. Shear bands were observed in all samples. Further, through- section microscopy of selected fractured samples revealed that the shear bands did not go across the enitre specimen for the coarser wires. The shear bands led to grain fragmention, with a reduction in grain aspect ratio as well as rotations away from the initial <111> orientations. The strength data were analysed based on a Weibull approach. The data could be rationalized in terms of failure from volume defects in coarser wires, with a high Weibull modulus, and from surface defects in finer wires, with a low Weibull modulus and greater variability. [ABSTRACT FROM AUTHOR]

This paper presents the analysis into microwave magnetic properties of magnetic microwires and their composites in the context of applications in wireless sensors and tunable microwave materials. It is demonstrated that the intrinsic permeability of wires has a wide frequency dispersion with relatively large values in the GHz band. In the case of a specific magnetic anisotropy this results in a tunable microwave impedance which could be used for distributed wireless sensing networks in functional composites. The other range of applications is related with developing the artificial magnetic dielectrics with large and tunable permeability. The composites with magnetic wires with a circumferential anisotropy have the effective permeability which differs substantially from unity for a relatively low concentration (less than 10%). This can make it possible to design the wire media with a negative and tunable index of refraction utilising natural magnetic properties of wires. [ABSTRACT FROM AUTHOR]

We have demonstrated the practicality of an ultrasensitive wrist-wear pulse active sensor that was first made using tellurium dioxide triangular microwires. The unusual growth direction of the α-TeO 2 triangular microwires was governed by a [110] axis. The α-TeO 2 microwires belong to the tetragonal structure with a space group of P4 1 2 1 2. Due to the gravitational force effect, the triangular microwires were encapsulated by polydimethylsiloxane (PDMS) and underwent a natural gravity-driven settling process during the PDMS solidification process, leading to the triangular microwires being placed on the substrate with a randomly horizontal orientation. When a compressive stress was applied to the α-TeO 2 –PDMS composite film, the shear forces were formed on the microwires׳ surface along with the [110] and/or [ 1 ¯ 1 ¯ 0] poling axis. As a result of the antisymmetric element of e 14 and − e 25 in the α-TeO 2 structure, the triangular microwires have created an obviously piezoelectric potential (piezopotential) ~3.2 V that was perpendicularly established along with the poling axis. On the basis of the unique triangular morphology and its physical properties, the piezopotential of the α-TeO 2 will not be canceled out even if the microwires׳ tips are pointed towards each other. Thus, the piezopotential can be accumulated across the top and bottom electrodes of the nanogenerator (active sensor). The α-TeO 2 triangular microwires can be acted upon as a useful active sensor for detecting the tiny physical motions, for instance, a pulse driven sensor, air pressure, and touchless control of smart devices. [ABSTRACT FROM AUTHOR]

Indium germanate (In 2 Ge 2 O 7 ) nanobelts and nano- and microwires have been synthesized by a thermal evaporation–deposition method and their luminescence properties have been investigated. High-resolution transmission electron microscopy shows the growth direction of the nanobelts. Cathodoluminescence in the scanning electron microscope and photoluminescence show the existence of a broad complex emission band with several components in the range 1.70–2.80 eV and a band at 3.20–3.30 eV. Comparison of the observed luminescence with the luminescence of GeO 2 suggests that some of the components are related to the presence of Ge 2 O 7 groups in the germanate crystal structure and not to the sheets of InO 6 octahedra of the structure. Waveguiding behaviour of In 2 Ge 2 O 7 nano- and microwires has been demonstrated under excitation with 325 nm light. Raman spectra of the nanobelts have characteristic peaks which could enable to correlate specific Raman features with the presence of In 2 Ge 2 O 7 and to use this technique for indium germanate assessment. [ABSTRACT FROM AUTHOR]

Amorphous S-doped and non-doped silicon oxide (SiO 2) one-dimensional structures with various morphologies are synthesized on Si substrates by vapor deposition with Ag 2 S as the precursor in a horizontal tube furnace. Curved microwires, grass-like microwires, S-doped microbelts, and straight S-doped microrods are obtained at the downstream of the furnace with different deposition temperatures in sequence. The microwires and microbelts are formed by the direct vapor-solid mechanism. The morphologies of microwires are largely determined by the inherent isotropy of their amorphous structure and the competitive growth in vapor phase. The microbelts are formed by the lateral growth of small microwires and the doped S played a critical role in their formation. However, the Ag–Si–S–O nanoparticles located at the growth ends suggests that the formation of S-doped SiO 2 microrods should be controlled by the vapor-liquid-solid mechanism. Both curved and grass-like microwires have similar photoluminescence behavior with strong blue/green/yellow bands and weak violent/red bands. However, S-doped microbelts exhibit strong violet/blue bands and relative strong a red band, and S-doped microrods exhibit low violet/blue bands and a strong red band. The obvious shifts in the intensities and wavelengths of the violet/blue/yellow bands are attributed to the morphology/size effects of microwires and microbelts, while the improved red-light emission is assigned to the doped S in microbelts and microrods. • S-doped SiO 2 nanobelts and nanorods are synthesized by vapor deposition. • S-doped SiO 2 nanobelts and nanorods are twist-free and straight. • Doped S determines the formation and morphology of the nanobelts. • Doped S can tune the optical properties of the nanobelts and nanorods. [ABSTRACT FROM AUTHOR]

Abstract: We studied magnetic and structural properties of granular Co x Cu100−x (5

Abstract: A new experimental method for the study of single magnetic domain wall dynamics in bistable microwires is presented. It raises new possibilities for experimenting with a single magnetic domain wall moving in an inhomogeneous magnetic field. Models for a wall with fixed length were confronted with experimental data obtained on amorphous glass-coated ferromagnetic microwire. These models qualitatively describe the observed behavior. The accord between models and experiment increases as the field disturbance decreases due to its inhomogeneity. A better match between experimental and model curves can probably be obtained if the changes in the wall dimensions and wall mass are taken into account. [Copyright &y& Elsevier]

Abstract: The investigation is focused on the effect of Cr incorporation for Co/Fe in (Co0.5Fe0.5)78−x CrxSi8B14 (x=0–12) amorphous microwires of 110μm diameter prepared by in-water quenching technique. The rise in crystallization onset T X1 with Cr addition revealed the elemental contribution against devitrification and a consequent thermal stability. Cr is unfavorable towards ferromagnetic ordering leading to a linear drop in Curie temperature T ca with its rise in concentration. The presence of low Cr content upto Cr-4at.% has been effective in drastically improving the Giant magneto-impedance (GMI) property. Cr content in the range of 4≤X≤10 has low magnetostriction and maximum field sensitivity in the as-quenched state. The GMI properties are further improved after annealing treatment. High content of Cr>10 is found to be deleterious towards GMI behavior and its consequent application as sensor material. [Copyright &y& Elsevier]

Abstract: Interaction of a single magnetic domain wall with an inhomogeneous magnetic field and distribution of local nucleation fields along glass-coated Fe77.5−x Ni x B15Si7.5 (x=0, 27.9, 34.9) microwires were experimentally studied. It was shown that the wall separating two axial domains and moving along the wire can be stopped by an inhomogeneous magnetic field. The wall remains stable and trapped in a local potential minimum after external fields are switched off. Wall coercivity increases with Ni content. For all samples the minimum of critical field for axial magnetization reversal was observed near the end of the wire. For samples with non-zero Ni content a distribution of nucleation fields lower than 950A/m was observed in regions far enough from the wire ends. In Ni-free samples the nucleation fields were higher than 950A/m. [Copyright &y& Elsevier]

Abstract: Single crystalline microwires and polycrystalline microtwists were self-assembled from X-shaped conjugated molecules through solution process in high yield. The excellent long-range optical waveguide ability and efficient light transfer between wires made the as-prepared microwires potential building blocks for complex optical devices at micrometer scale. By slight structural change, well-dispersed polycrystalline microtwists were also successfully obtained. We further demonstrated that such chiral structures could also be used as optical waveguiding materials. The investigation of photo waveguide property in the well-dispersed single microtwist is the first demonstration of chiral microstructures in the application of optical waveguide, which opens the possibility of coupling the chirality of material to that of light. [Copyright &y& Elsevier]

Abstract: In shape memory alloys, the reversible phase transformations between austenite and martensite give rise to superelasticity and shape memory properties. Here we systematically study the sample size dependence of these properties and the associated transformations in polycrystalline shape memory alloy microwires with a bamboo grain structure, i.e. where the wire diameter is completely spanned by individual grains. Cu–Al–Ni wires with diameters ranging from ∼500 down to ∼20μm are fabricated by the Taylor liquid processing technique, and are characterized by both isothermal uniaxial tensile testing and mechanically constrained thermal cycling. We observe size effects in both the transformation stresses and temperatures. What is more, we find that the stress hysteresis in a mechanical cycle and the temperature hysteresis in a thermal cycle both increase with decreasing wire diameter, particularly for wires smaller than 100μm. A direct consequence of the increased hysteresis is enhanced energy dissipation (i.e. damping capacity) in smaller wires. We also discuss possible physical origins of the observed size effects, including interface and surface energies, stored elastic energy, heat transfer and internal friction. [Copyright &y& Elsevier]

Abstract: It is shown that copper microwires composite media attenuates microwave reflection of metallic surfaces. We show how the distance to the metallic surface, as well as the length and volume fraction of microwires, determine the frequency of maximum absorption and the return loss level. Furthermore, we were able to fit the experimental results with a theoretical model based on Maxwell-Garnett mixing formula. [Copyright &y& Elsevier]

Abstract: The effect on the gas sensitivity of point heterocontact between single walled nanotubes (SWNTs) and a gold microwire is demonstrated for the first time. Au-SWNT heterocontact sensors exhibit high sensitivity to NH3 and NO2 vapors with fast response and relaxation and demonstrate that these two gases can be distinguished based on the direction of charge transfer between the analyte and the SWNTs. The mechanism of sensing is associated with formation of a thin conductive channel between Au and SWNT, but the sign of the resistance change is controlled by the SWNT. [Copyright &y& Elsevier]

Abstract: Polyaniline (PANI)/TiO2 hybrid microwires with diameter of 160–180nm were prepared through the sol–gel process of TiO2 and in situ polymerization of aniline in the microchannels of anodic aluminum oxide (AAO) template. The structure, morphology and properties of the microwires were characterized with scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), fluorescence spectroscopy (FL), ultraviolet–visible spectroscopy (UV–vis) and X-ray photoelectron spectroscopy (XPS). The results show that the regular arrangement of microwires, with well-dispersed inorganic phase in the organic matrix is formed. Also, the shape of the hybrid microwires is similar to that of the template channel and the diameter of microwires is smaller than that of the template channels due to the shrinkage of volume during the sol–gel process. XPS analysis confirms that there are a lot of leftover OH groups in the hybrid system owing to the lower treatment temperature of TiO2 gel and interactions between PANI and TiO2, which is consistent with the results of UV–vis and FL analysis. The XRD data confirms that no obvious diffraction peak is observed in hybrid microwires at the reported treatment temperature (180°C). FL spectra shows that the interaction and energy band match between PANI and TiO2 cause in the blue shift of the emission peaks of hybrid microwires. It is obvious that with the applied approach, the organic/inorganic hybrid materials with slight phase separation, equable distribution, well-ordered structure and unique function can be prepared easily. [Copyright &y& Elsevier]

Abstract: Amorphous magnetic microwires exhibit outstanding magnetic characteristics as giant Barkhausen jump or nearly non-hysteretic behaviour that make them very suitable as sensing elements in various devices. In this article, we overview the different families of microwires and summarise most relevant results in connection with the magnetoelastic interlayer interactions in multilayer microwires. Improved magnetic behaviour can be observed in bi-layer microwires consisting of a magnetic nucleus coated by insulating cover. By employing combined sputtering and electroplating techniques, a novel series of multilayered magnetic microwires have been recently introduced. They consist typically of a magnetic nucleus and several shells having insulating and/or metallic nature, the latter magnetic or not. The magnetic character of the multilayer microwire will then depend on the magnetoelastic coupling between layers. External layers induce compressive stresses on the soft amorphous nucleus resulting in induced axial or circular anisotropies depending on magnetostriction sign. In a similar way, reduction of measuring temperature results in tensile stress as a consequence of different thermal expansion coefficients of various layers. [Copyright &y& Elsevier]

Abstract: We describe a modification of the Harper–McGinty microdrive for use with extracellular, microwire recording in conscious, chronically prepared rabbits. Improvements over existing designs are in ease of assembly and mechanical stability. The microdrive is easily fabricated with hand tools and readily available parts. In addition, assembly of the microdrive utilizes epoxy, avoiding the difficult task of soldering stainless steel parts. Finally, the microdrive is mounted directly to the skull enhancing mechanical stability and eliminating the need to allow space for screw travel. Importantly, this microdrive has proven to be durable as well as functional in our preparation. [Copyright &y& Elsevier]

Abstract: We present a facile method to prepare helical polyaniline (PANI) microwires or rods guided by poly(acrylic acid) (PAA). The average length and diameter of the helical strands were about 3.5μm and 500nm, respectively. The pitch distance was about 400nm. The morphology of the helical PANI microwires was affected by the concentration of PAA. As the concentration was decreased to below 0.05mg/ml, helical wire- or rod-like products were observed. The structure of the helical polyaniline microwires were characterized by means of TEM, SEM, XRD, FTIR and UV–vis spectroscopy. [Copyright &y& Elsevier]

The monomolecular compound ethylenedithiotetrathiafulvalene (EDT-TTF(CONHMe)2) and the charge transfer salt tetramethyltetraselenafulvalene (TMTSF)2ClO4 were successfully recrystallized using the drop casting method. Samples of various sizes were obtained, with widths as small as 300nm and thicknesses above 30nm. The length of the samples can reach 1mm. The conductivity of the former compound, σ ≉ 3.10-7Scm-1 is typical of neutral TTF derivatives. Its bulk mobility is about μb ≉ 1cm2/Vs. For the thinnest samples of (TMTSF)2ClO4, the two point conductivity is dominated by the sample conductivity instead of the contact resistance. [Copyright &y& Elsevier]

There is an increasing necessity to record the deformation characteristics of microelements often consisting of freestanding foils and wires due to their increasing demand in engineering applications, where they are being used in the automotive industry, micromachines, special sensors, etc. The data required are either mechanical or thermal such as Young’s moduli, stress–strain values, fatigue and thermal strain data. Due to the size effect these data cannot be taken from macrospecimens, thus special testing procedures were introduced. For the mechanical properties tensile tests were used for the freestanding foils and wires. Laseroptical sensors based on the speckle correlation method were applied to determine non-contacting strain values with high strain resolution. Equipped with a special air furnace mechanical data could be obtained up to 300 °C. For thermal strain measurements a laser speckle based dilatometer (LSBD) was designed. The following materials data are presented and discussed: Thermal expansion data, mechanical and fatigue properties of Cu foils (electrodeposited (ED), rolled and annealed) and wires with varying thickness. A pronounced thickness effect was detected. The applicability and limitations of the testing equipment used are discussed. [Copyright &y& Elsevier]

• Fabrication of singular Sn doped NiO microwires by a one-step vapor-solid method. • Tailored optical properties as a function of the selected-Sn precursor. • Novel waveguiding behaviour of the Sn doped microwires. Sn-doped NiO microwires with tailored structure of defects, optical properties and waveguiding behaviour were fabricated by a one-step vapor-solid method. The presence of metallic Sn or SnO 2 in the precursor mixture favours the formation of elongated microstructures with singular morphologies. This geometry, not explored so far, provides an increased surface to volume ratio and a characteristic morphology, which is of potential interest in a wide range of surface properties and optoelectronic functionalities. In this work, the structural, compositional, electronic and optical properties of the microwires have been analyzed as a function of Sn precursor. Depending on the employed Sn precursor, the optical properties such as their luminescence or waveguiding behaviour can be tailored. In some of the analysed microwires a red laser can be guided along the microstructure. This behaviour has not been previously reported for NiO so far, hence increasing the functionality and applicability of this material. [ABSTRACT FROM AUTHOR]

The substituted pyrrole monomer, N–(2–cyanoethyl)pyrrole, was electropolymerised in a 70% water and 30% ethanol solution with ClO 4 – and H 2 PO 4 – as the dopant species to give nanowires at short electropolymerisation times and microwires at longer deposition periods. On adding toluene to the electropolymerisation solution, hollow microtubes were formed. This was attributed to the adsorption of toluene droplets at the electrode surface which served to separate the dopants from the monomer, with the monomer being highly soluble in the toluene droplet and the inorganic dopants soluble in the water/ethanol mixture. As a result electropolymerisation was confined to the toluene-water/ethanol interface. These polymer systems exhibit redox activity with the oxidation wave centred at about 0.40 V vs SCE, and the broader reduction wave positioned between 0.75 V and 0.25 V vs SCE. Although N-substitution reduces the conductivity of the polymer, various copper deposits, including cubes, leaves and hierarchical structures were deposited at the microwires and microtubes using high overpotentials. The hierarchical structures were wrapped around the microtubes at considerable distances, typically 3–4 µm, from the substrate. • N-substituted polypyrrole nanowires, microwires and open microtubes were electrochemically formed. • Copper cubes and leaf-like structures were electrodeposited onto the N-substituted polypyrrole nanowires/microwires. • Copper hierarchical structures were wrapped around the microtubes at considerable distance from the substrate electrode. [ABSTRACT FROM AUTHOR]

Understanding piezotronic correlated carrier recombination behavior in quantum wells is essential for their applications. In this work, we have studied the influence of piezotronics on carrier recombination processes in single InGaN/GaN multiple quantum wells microwire (MQW-MW) by using steady-state and time-resolved spectroscopies. We conclude that mechanical strain induced piezotronics promotes the charge separation of excitons in space, and slows down the recombination rate of free carriers. The proposed model is supported by three independent experiments: photoluminescence experiment of MQW-MW before and after peel off, strain dependent TRPL experiment, and excitation fluency dependent PL intensity experiment. Our study could provide a guideline for the application of piezotronic in MQW-MW-based optoelectronic devices. In this work, non-contact spectroscopy methods were used to study carrier recombination behavior in single InGaN/GaN multiple quantum wells microwire (MQW-MW) with various compress and tensile strains, through which the stress induced ultrafast charge spatial separation due to the piezotronic effect were presented. [Display omitted] • Piezotronics on carrier recombination dynamics in single InGaN/GaN multiple quantum wells is studied. • Piezotronics correlated carrier recombination model is supported by three independent experiments. • Piezo-potential promotes charge separation of excitons in space and slows down the trapping or recombination rate of free carriers. [ABSTRACT FROM AUTHOR]

The creation of liquid metal alloys that are reacted with species in solution is a relatively new approach to the synthesis of functional nanomaterials. In this work we explore the liquid Ag–Ga system and its interaction with redox active species in aqueous solution in the areas of heterogeneous catalysis and charge transfer complex formation. It was found that when Ag is alloyed with Ga that solid microwires of Ag 2 Ga were formed over time with a width of ca. 1–1.5 µm of up to 160 µm in length. This Ga/Ag 2 Ga composite was then investigated for the discolouration of methylene blue dye in both the liquid and solid state where little difference in activity was found resulting in 40% discolouration after 30 min. However, if nitrogen gas was passed through the liquid form of the catalyst the conversion efficiency of the catalyst increased significantly up to 99% after 1 min and could be re-used for up to 10 cycles. In addition, the catalytic conversion of 4-nitrophenol to 4-aminophenol at the liquid Ga/Ag 2 Ga catalyst was significantly greater than liquid Ga and could be reused for up to 5 cycles. The interaction of liquid Ag–Ga with the well-known electron acceptor 7,7,8,8-tetracyanoquinodimethane (TCNQ) was also studied where it was found that a reaction only occurred immediately after mixing Ag microparticles with liquid Ga and before any Ag 2 Ga microwires were formed. The reaction conditions of bubbling nitrogen gas through the liquid Ag–Ga catalysts in an acetonitrile solution of TCNQ resulted in the time dependent formation of various morphologies of the semi-conducting charge transfer complex AgTCNQ. This work shows that alloying metals with Ga can result in the time dependent formation of a variety of materials under different reaction conditions when exposed to solution based redox active species. Creating a liquid Ag–Ga alloy results in the formation of microwires of Ag 2 Ga that can be used as a catalyst for methylene blue degradation and nitrophenol conversion to aminophenol. This system can also be used to generate semiconducting crystals of AgTCNQ with different morphologies when reacted with TCNQ. [Display omitted] • Ag microparticles when mixed with liquid Ga form microwires of Ag 2 Ga on the surface of liquid Ga over time • This liquid Ga/Ag 2 Ga can be used as a recyclable heterogeneous catalyst when agitated via nitrogen gas purging • The initially formed Ag–Ga liquid metal can be reacted with TCNQ in solution to form microstructured semiconducting AgTCNQ [ABSTRACT FROM AUTHOR]

[Display omitted] • Nanocrystalline Fe-containing GdTbCoAl high-entropy-metallic-glass were attained. • Curie temperature is tuned by Fe-doping in a wide temperature range of 81–108 K. • Magnetic entropy change 7.6–8.9 J kg−1 K−1 for 5 T were achieved. • The dual-phase structure with T C distribution enhances the cooling efficiency. Through designing the composition and processing approach, the non-equiatomic (Gd 36 Tb 20 Co 20 Al 24) 100-x Fe x (x = 0, 1, 2 and 3 at.%) high-entropy-metallic-glass (HE-MG) alloy microwires were successfully fabricated by melt-extraction technique. The microstructure and magnetocaloric properties of the microwires were systematically investigated. The microwires possess tunable Curie temperatures, i.e. 81–108 K, above the typical rare-earth (RE) containing HE-MG reports. The high Curie temperatures are attributed to the designed composition. Magnetocaloric response peak values of Fe-containing GdTbCoAl alloy microwires range 7.6–8.9 J kg−1 K−1 (5 T), which are comparable to those of many outstanding RE-containing magnetocaloric HE-MGs. The characteristics of the melt-extraction method, combining with compositional effects, favor the formation of amorphous and nanocrystalline phases. The increase in the cooling efficiency for microwires with higher Fe content can be attributed to the broadening of the Curie temperature distribution induced by the composition difference between nanocrystalline phase and amorphous matrix. The designed composition and the melt-extraction processing approach for Fe-containing GdTbCoAl alloys can tune their Curie temperatures towards a temperature range of natural gas liquefaction and improve their magnetocaloric properties. This demonstrates that Fe-containing GdTbCoAl HE-MG composite microwires have great potential as high-performance magnetic refrigerants. [ABSTRACT FROM AUTHOR]

• The novel medium-entropy alloys were fabricated by melt-extraction and exhibit excellent magnetic entropy change. • The microwires show typical amorphous characteristics and second-order phase transition. • The microstructure of microwires near room temperature is studied by in-situ HEXRD. A melt-extracted HoErCo medium-entropy alloy (MEA) with large magnetic entropy change and excellent magnetic refrigerant capacity is successfully designed in this study. The microstructure evolution of these microwires near room temperature is studied by an in-situ high energy synchrotron X-ray diffraction (HEXRD). The wires show typical amorphous characteristics during room temperature to 250 K. For a field change of 5 T, the maximum magnetic entropy change (-Δ S M max) of the microwires reaches a maximum value of 15.0 J•kg−1 K−1. Magnetization measurements revealed a paramagnetic to ferromagnetic phase transition at T C ~16 K. The refrigerant capacity (RC) and relative cooling power (RCP) are 527 J•kg−1 and 600 J•kg−1, respectively. This investigation highlights the potential of HoErCo MEA microwires as promising magnetocaloric effect materials for cryogenic applications of magnetic cooling. [ABSTRACT FROM AUTHOR]

Developments in interfacial shear rheometers have considerably improved the quality of experimental data. However, data analysis in interfacial shear rheometry is still an active field of research and development due to the intrinsic complexity introduced by the unavoidable contact of the interface with, at least, one supporting bulk subphase. Nonlinear velocity profiles, both at the interface and the bulk phases, pervade the system dynamical behavior in the most usual experimental geometries, particularly in the case of soft interfaces. Such flow configurations demand data analysis schemes based on the explicit calculation of the flow field in both the interface and the bulk phases. Such procedures are progressively becoming popular in this context. In this review, we discuss the most recent advances in interfacial shear rheology data analysis techniques. We extensively review some recently proposed flow field-based data analysis schemes for the three most common interfacial shear rheometer geometries (magnetic needle, double wall-ring, and bicone), showing under what circumstances the calculation of the flow field is mandatory for a proper analysis of the experimental data. All cases are discussed starting at the appropriate hydrodynamical models and using the equation of motion of the probe to set up an iterative procedure to compute the value of the complex Boussinesq number and, from it, the complex interfacial viscosity or, equivalently, the complex interfacial modulus. Moreover, two examples of further extensions of such techniques are proposed, concerning the micro-button interfacial shear rheometer and the potential application of interfacial rheometry instruments, together with adapted flow field-based data analysis techniques, for bulk rheometry, particularly in the case of soft samples. Unlabelled Image • Flow field-based data analysis (FFBDA) techniques can handle nonlinear velocity profiles appearing in usual ISR geometries. • FFBDA techniques yield an accurate separation of interfacial and bulk phase drags, and more precise values of G' and G". • Nowadays, FFBDA techniques can be implemented in real-time control and measurement software of interfacial rheometers. • ISR geometries, together with FFBDA techniques, appear to be very promising for bulk rheology studies of soft materials. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a new route is described in order to obtain wires which can reach a few hundreds of micrometers long. ZnO rod is sintered at 900°C for 10h in air. Then the centimetric rod is placed in an optical furnace. The optical furnace allows to reach a thermal gradient of about 350°C/cm. In a first step, the vaporization of ZnO occurs, and in a second step the condensation of ZnO on the rod appears and leads to the growth of ZnO microwires (MWs). In few minutes, the MWs can reach in the c-direction a dimension higher than 100μm with a diameter close to ten microns. The shape of the MWs is hexagonal which is consistent with the crystal structure of ZnO (P63mc group). The MWs exhibit a high crystalinity. [Copyright &y& Elsevier]

High-entropy alloys (HEA) represent potentially disruptive materials across multiple industries, especially for refrigeration technologies. Building metal components layer-by-layer increases design freedom and manufacturing flexibility, thereby enabling high magnetic thermal properties of the multicomponent alloy. However, excessive alloying elements could limit the mass production potential, while prolonging the time to market. Here we demonstrate that a high performance magnetocaloric material can be synthesized from only three elements, HoErFe, by taking advantage of the combination of rare earth and transition elements. Novel medium-entropy alloys (MEA) are prepared by melt-extraction and exhibit excellent magnetocaloric properties. The amorphous/nanocrystalline structure of the microwires, which is confirmed by both transmission electron microscopy (TEM) and X-ray diffraction (XRD), gives the primary contribution to the MCE. The microwires undergo a ferromagnetic-paramagnetic (FM-PM) transition near the Curie temperature (T C = ~44 K), and a spin-glass (SG) behavior could be observed below the T C. The maximum magnetic entropy (-ΔS M max) was 9.5 J kg−1 K−1 under a field change of 5 T. Meanwhile, the refrigerant capacity (RC) and the relative cooling power (RCP) of the alloy microwires were 450 J·kg−1and 588 J kg−1, respectively. The high refrigeration efficiency and high magnetocaloric effect that is reversible make these novel metallic microwires attractive working materials for low-temperature magnetic refrigeration applications. • The novel medium-entropy alloys are prepared by melt-extraction and exhibit excellent magnetocaloric properties. • The wire composite shows a spin-glass behavior below Curie temperature. • The amorphous/nanocrystalline structure of the microwires exhibit enhanced magnetocaloric effect. [ABSTRACT FROM AUTHOR]

• Fe- and Co-based glass-coated magnetic microwires were used for cell manipulation; • Microwires create a strong and well-localized magnetic field at the ends; • Two concepts of manipulator systems which require specific magnetic properties were discussed; • 1D-manipulation constitutes the use of a single microwire as a pin system; • 2D-manipulation system should contain at least three microwires operated individually; • The choice of microwire for certain applications is correlated with their magnetic microstructure. The application of magnetic nanoparticles allows labeling the cell for its manipulation via the external magnetic field. In this work, it is proposed to use glass-coated magnetic microwires as a magnetic pin system to create a strong and well-localized magnetic field at the end of such microwires. Magnetic microwires manufactured by the Taylor − Ulitovsky method exhibit tunable magnetic properties correlated with their unique micromagnetic structure. The control of magnetic properties can be achieved by, for example, the chemical composition of the wire: Fe-based microwire shows bistable hysteresis and thus strong stray fields at the ends, while Co-based one demonstrates S-shaped hysteresis with almost zero remanent magnetization because of a closed domain structure. In this research, we discovered by theoretical calculation and experiments the usability of both kinds of microwires for different approaches of cell manipulations. [ABSTRACT FROM AUTHOR]

The effect of tensile stresses on the magnetic properties of amorphous microwires with positive magnetostriction has been studied. It has been determined that the experimental dependence of coercivity on the tensile stresses is reversible and consists of linear and square root parts. The evolution of an average stress level in the "core" and surface domain layer has been theoretically estimated depending on the external tensile stress. The value of internal stress level may vary from 150 to 600 MPa in "core" for microwires with different ratio of amorphous metallic nucleus diameter to thickness of glass shell. Crucial differences of tension of glass-coated and uncoated microwires have been investigated. The analysis of these differences with relation to effect under tension has been performed. • Coercivity dependence on the stress is reversible for amorphous microwires. • Coercivity dependence on the stress consists of linear and square root working areas. • A decrease in the initial average stress leads to a decrease in the rate of coercivity increase. • An increase in the initial average stress leads to an increase in the "linear" region of tension. • Adhesion effects on the peculiarities of magnetization reversal process of microwires. [ABSTRACT FROM AUTHOR]