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We investigate the magnetic domain behavior of bulk Fe 3 GaTe 2 , a van der Waals (vdW) ferromagnet characterized by a Curie temperature (T c) of 350–380 K and significant perpendicular magnetic anisotropy (PMA). Using magnetic force microscopy, we present the evolution of magnetic domains during cooling from T c to 300 K, and analyze magnetic domain images along the hysteresis loop at 4.2 K. Our observations reveal a strong temperature-dependent domain structure. From room temperature to T c , we observe the coexistence of stripe, bubble, and surface spike domains. In contrast, in the zero-field cooled state at 4.2 K, irregular stripe and enclosed ring domains predominate. The correlation between global and local magnetization suggests that the hysteretic behavior in the magnetization results from the rapid nucleation of a few stripe domains evolving into intricate dendritic patterns, a phenomenon not previously observed in other vdW systems. These findings highlight the delicate balance among interlayer exchange coupling, thermal fluctuations, and PMA in the formation of various domains in a 3D vdW system, where shape anisotropy is minimized. [ABSTRACT FROM AUTHOR]

Magnetic force microscopy (MFM) is long established as a powerful tool for probing the local stray fields of magnetic nanostructures across a range of temperatures and applied stimuli. A major drawback of the technique, however, is that the detection of stray fields emanating from a sample's surface rely on a uniaxial vertical cantilever oscillation, and thus are only sensitive to vertically oriented stray field components. The last two decades have shown an ever-increasing literature fascination for exotic topological windings where particular attention to in-plane magnetic moment rotation is highly valuable when identifying and understanding such systems. Here, we present a method of detecting in-plane magnetic stray field components, by utilizing a split-electrode excitation piezo that allows the simultaneous excitation of a cantilever at its fundamental flexural and torsional modes. This allows for the joint acquisition of traditional vertical mode images and a lateral MFM where the tip–cantilever system is only sensitive to stray fields acting perpendicular to the torsional axis of the cantilever. [ABSTRACT FROM AUTHOR]

Understanding the internal magnetization structure of an individual ferromagnetic nanoparticle (MNP) is crucial for deciphering its magnetic characteristics. Unfortunately, while certain techniques can measure the magnetic properties of an individual MNP, they fall short of accurately detecting the internal magnetization structure. In this work, micromagnetic simulations were employed to construct the internal magnetization structure of an individual CoFe2O4 (CFO) nanopyramid, and the energy jump behavior during the magnetization process was successfully explained, with simulation results aligning with dynamic cantilever magnetometry (DCM) experimental outcomes. Subsequently, the external stray field of the nanopyramid was simulated, and the stray field gradient map revealed distinct bright and dark regions corresponding to the reverse and forward saturation magnetizations of the CFO nanopyramid. This result is possible to be verified by magnetic force microscopy (MFM) measurements of individual CFO nanopyramids. The confidence in the accuracy of the simulated internal magnetization structure was significantly enhanced by independently verifying the micromagnetic simulation results through DCM and MFM experiments. Our work proposes a convenient and cost-effective method for studying the internal magnetization structure of individual MNPs. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the effect on the structure and magnetic properties of partial Pd substitution by Gd in Fe–Pd thin films of nominal composition Fe56Pd44−xGdx (x = 1, 3, 5, and 7), deposited onto Si(100) and Si(100)/SiO2 substrates by thermal evaporation. Several techniques contribute to the characterization of their microstructure and magnetic properties, such as x-ray diffraction (XRD), scanning electron microscopy, alternating gradient field magnetometry, and magnetic force microscopy (MFM). X-ray diffraction shows that the as-deposited films are either amorphous or contain a disordered FePd phase, depending on the film thickness. The transformation of disordered fcc-FePd into ordered fct-FePd has been induced by a heat treatment at 530 °C for 4 h. The addition of gadolinium leads to a reduction in the coercivity as a consequence of the emergence of soft phases and of the progressive reduction of the fct-FePd phase, which is primarily responsible for the observed maze magnetic domains. The exchange coupling between the soft phase and the hard fct-FePd phase is demonstrated by first-order reversal curves (FORCs). [ABSTRACT FROM AUTHOR]

This study investigates the out-of-plane magnetization component of electrodeposited Ni90Fe10 thin films grown under different applied magnetic field conditions. The formation of stripe domains is gradual, as there is a thickness range in which the transcritical shape appears in the hysteresis loops, while only magnetic ripples are measured in the magnetic force microscopy images. For instance, samples deposited under the residual magnetic field generated by the switched-off magnetic stirrer exhibit the transcritical shape in the in-plane hysteresis loops at a thickness of 400 nm, even though corresponding magnetic force microscopy images do not reveal the presence of stripe domains. When a perpendicular magnetic field of 100 Oe is applied during growth, stripe domains become visible in microscopy images, along with the transcritical shape in the hysteresis loop at 400 nm. This implies that the critical thickness for stripe formation can be reduced by applying a perpendicular magnetic field during electrodeposition. We have experimentally confirmed that the larger the magnetic field applied in the out-of-plane direction during growth, the smaller the critical thickness. These results underscore the importance of controlling the external magnetic field during electrodeposition for more effective tuning of the magnetic textures in electrodeposited Ni90Fe10 films. [ABSTRACT FROM AUTHOR]

We demonstrate experimentally and numerically the control of magnetization circulation of the closure domain state in thin permalloy squares divided diagonally into four dipolar-coupled isosceles triangles. The control over the magnetization circulation was achieved by the mutual application of a suitable external in-plane magnetic field and interaction with a magnetic force microscopy (MFM) tip. Numerical simulations confirm that the proposed switching protocol is valid for the broad range of MFM tips. Experiments performed on four diagonally cut squares show that this method is robust against slight imperfections in the fabrication process. Moreover, by varying the polarity of the applied field and the direction of the MFM scanning, proper symmetry response of the switching method is observed. [ABSTRACT FROM AUTHOR]

Micrometer-sized magnetic particles have been widely used in magnetic force microscopy, magnetic resonance force microscopy, and bio-sensing. To quantitatively interpret the data obtained with magnetic particles, it is important to know the magnetic properties of the particles. However, the magnetic moment of individual particle is usually too small to be measured by common instruments for samples with large volume. Here, we present a method to characterize magnetic microspheres using patterned FePt thin films as standard samples. The FePt thin film in the L 1 0 phase has perpendicular magnetic anisotropy, and the patterned features can be magnetized to near single-domain magnets, which make them suitable standards for magnetic sphere calibration with magnetic force microscopy. Multiple linear regression is used to analyze the frequency shift images and obtain the effective dipole moment of the spheres. The position of the dipole moment is obtained by minimizing the residuals in multiple linear regression with a gradient descent algorithm. Three NdFeB spheres of different diameters were measured. It was found that the magnetization increases with the increase in the diameter of the sphere, possibly due to the weakening of ferromagnetism on the surface. [ABSTRACT FROM AUTHOR]

Target skyrmions (TSks) are topological spin textures where the out-of-plane component of the magnetization twists an integer number of k- π rotations. Based on a magnetic multilayer stack in the form of n × [CoFeB/MgO/Ta], engineered to host topological spin textures via dipole and DMI energies, we have stabilized 1 π , 2 π , and 3 π target skyrmions by tuning material properties and thermal-excitations close to room temperature. The nucleated textures, imaged via Kerr and Magnetic Force Microscopies, are stable at zero magnetic field and robust within a range of temperatures (tens of Kelvin) close to room temperature (RT = 292 K) and over long time scales (months). Under applied field (mT), the TSks collapse into the central skyrmion core, which resists against higher magnetic fields (≈ 2 × TSk annihilation field), as the core is topologically protected. Micromagnetic simulations support our experimental findings, showing no TSk nucleation at 0 K, but a ≈ 30 % probability at 300 K for the experimental sample parameters. Our work provides a simple method to tailor spin textures in continuous films, enabling free movement in 2D space and creating a platform transferable to technological applications where the dynamics of the topological textures can be exploited beyond geometrical confinements. [ABSTRACT FROM AUTHOR]

2D magnetic semiconductors exhibit great potential for next‐generation spintronics, but realizing their full capabilities has been hindered by the low Curie temperatures (Tc) below 50 K observed in current materials. Here, a new mechanism to substantially enhance the Tc of 2D semiconducting materials through incorporating both in‐plane and out‐of‐plane superexchange interactions enabled by structural design is demonstrated. Specifically, monolayer Cr2Se3 is synthesized with a five‐layer Se–Cr–Se–Cr–Se atomic structure using molecular beam epitaxy (MBE). This unique structure not only possesses optimized in‐plane superexchange interaction but also incorporates out‐of‐plane Cr–Se–Cr couplings. Scanning tunneling spectroscopy (STS) and angular‐resolved photoemission spectroscopy (ARPES) confirm its semiconducting nature. Remarkably, the ferromagnetic phase transition observed by ARPES and Magnetic Force Microscopy (MFM) indicated that its Tc is up to 230 K. This not only establishes a new record for Tc in 2D ferromagnetic semiconductor materials but also introduces a novel approach to modulating materials' properties by manipulating the vertical dimension in 2D materials. [ABSTRACT FROM AUTHOR]

2D magnetic semiconductors exhibit great potential for next‐generation spintronics, but realizing their full capabilities has been hindered by the low Curie temperatures (Tc) below 50 K observed in current materials. Here, a new mechanism to substantially enhance the Tc of 2D semiconducting materials through incorporating both in‐plane and out‐of‐plane superexchange interactions enabled by structural design is demonstrated. Specifically, monolayer Cr2Se3 is synthesized with a five‐layer Se–Cr–Se–Cr–Se atomic structure using molecular beam epitaxy (MBE). This unique structure not only possesses optimized in‐plane superexchange interaction but also incorporates out‐of‐plane Cr–Se–Cr couplings. Scanning tunneling spectroscopy (STS) and angular‐resolved photoemission spectroscopy (ARPES) confirm its semiconducting nature. Remarkably, the ferromagnetic phase transition observed by ARPES and Magnetic Force Microscopy (MFM) indicated that its Tc is up to 230 K. This not only establishes a new record for Tc in 2D ferromagnetic semiconductor materials but also introduces a novel approach to modulating materials' properties by manipulating the vertical dimension in 2D materials. [ABSTRACT FROM AUTHOR]

Atomic force microscopy (AFM)-based analysis on the corrosion inhibition properties of aqueous black seed extract for mild steel exposed to 3.5% NaCl solution is reported here. At ~ 600 ppm inhibitor concentration, corrosion rate and inhibition efficiency are found to be ~ 0.18 ± 0.1 mpy and ~ 94%, respectively. The superior corrosion inhibition is due to the adsorption of the phytochemicals onto the metallic surface, as confirmed from spectroscopic analysis. Findings show the suitability of the black seed extract for practical applications at neutral pH and room temperature. AFM and magnetic force microscopy indicate lower surface roughness and nearly pristine topography for the inhibitor-protected specimens. In situ AFM analyses indicate delayed formation of surface irregularities for the inhibitor-protected specimens. The obtained results clearly show the superior corrosion inhibition efficiency of the aqueous black seed extract against mild steel under simulated sea water condition. [ABSTRACT FROM AUTHOR]

The electronic orders in kagome materials have emerged as a fertile platform for studying exotic quantum states, and their intertwining with the unique kagome lattice geometry remains elusive. While various unconventional charge orders with broken symmetry is observed, the influence of kagome symmetry on magnetic order has so far not been directly observed. Here, using a high‐resolution magnetic force microscopy, it is, for the first time, observed a new lattice form of noncollinear spin textures in the kagome ferromagnet in zero magnetic field. Under the influence of the sixfold rotational symmetry of the kagome lattice, the spin textures are hexagonal in shape and can further form a honeycomb lattice structure. Subsequent thermal cycling measurements reveal that these spin textures transform into a non‐uniform in‐plane ferromagnetic ground state at low temperatures and can fully rebuild at elevated temperatures, showing a strong second‐order phase transition feature. Moreover, some out‐of‐plane magnetic moments persist at low temperatures, supporting the Kane–Mele scenario in explaining the emergence of the Dirac gap. The observations establish that the electronic properties, including both charge and spin orders, are strongly coupled with the kagome lattices. [ABSTRACT FROM AUTHOR]

We are entering an era of re-electrification, seeking high-power density electrical machines with minimal resource use. Significant performance gains in electrical machines have been achieved through precise manufacturing processes, including the shaping/cutting of soft magnetic materials. However, most studies have evaluated magnetic performance at a macro level, focusing on components, while the fundamental mechanisms, e.g., how the micromagnetic behaviour is affected by mechanical interference, remain unclear. In this study, we examine the impact of sub-micron deformations at opposing strain rates (10−2 to 101 s−1) on the micromagnetic behaviour of soft magnetic non-oriented electrical steel. Using a diamond probe to indent within a single grain of polycrystalline material at different velocities, we induce quasi-static and dynamic mechanical loading. Our analysis, employing magnetic force microscopy, transmission Kikuchi diffraction, and scanning transmission electron microscopy with a pixelated detector, reveals that magnetic texture disturbances rely on the time-dependent dislocation dynamics of the Fe-BCC material. Additionally, we compress micro-pillars to further investigate these effects under bulk-isolated deformation. These findings highlight the importance of considering even ultra-small loads, such as nano-indentations and micro-pillar compressions, in the manufacturing of next-generation electric machines, as they can affect magnetic texture and performance. Mechanical deformations affect magnetic properties of electrical steels, impacting machine efficiency. Here, authors demonstrate that sub-micron deformations at different strain rates alter micromagnetic behaviour of non-oriented electrical steel due to time-dependent dislocation dynamics. [ABSTRACT FROM AUTHOR]

Magnetic resonance force microscopy (MRFM) describes a range of approaches to detect nuclear spins with mechanical sensors. MRFM has the potential to enable magnetic resonance imaging with near-atomic spatial resolution, opening up exciting possibilities in solid state and biological research. In many cases, the spin-mechanics coupling in MRFM is engineered with the help of periodic radio frequency pulses. In this paper, we report that such pulses can result in unwanted parametric amplification of the mechanical vibrations, causing misinterpretation of the measured signal. We show how the parametric effect can be canceled by auxiliary radio frequency pulses or by appropriate post-correction after careful calibration. Future MRFM measurements may even make use of the parametric amplification to reduce the impact of amplifier noise. [ABSTRACT FROM AUTHOR]

The combination of focused electron beam induced deposition (FEBID) and magnetic force microscopy (MFM) has opened up new possibilities in nanoscale magnetic imaging. FEBID offers precise control over the dimensions and magnetic properties of the MFM probes, enabling the development of high-performance magnetic tips with enhanced capabilities compared to conventional ones. These improved tips offer superior resolution, sensitivity, and versatility in nanoscale magnetic surface characterization. Here, we compare the performance of a commercial MFM tip and a FEBID-grown Fe tip in a Ni80Fe20/NdCo5 film. The FEBID tip exhibited superior lateral resolution for topography imaging, likely due to its sharper and well-defined geometry, with a tip diameter of approximately 20 nm. MFM measurements further confirmed this advantage, revealing better-defined magnetic domains and higher magnetic contrast with the FEBID-functionalized probes compared to the commercial tip. This improvement can be attributed to the possibility to optimize the tip-sample magnetic interaction for the FEBID tip. By reducing the lift height of the second pass, we were able to bring the tip closer to the sample, enhancing the magnetic signal without introducing significant topographic artifacts. Overall, these findings highlight the potential of FEBID for creating high-resolution and high-sensitivity MFM tips. [ABSTRACT FROM AUTHOR]

We present a novel method for fabricating dense and nanopatterned porous cobalt ferrite (CoFe2O4) thin films with a remarkable thickness of 65 nm, achieved through direct block copolymer self‐assembly. By decomposing the block copolymer and inducing crystallization of the spinel phase, we successfully produce films exhibiting quasi‐hexagonal arrays of pores with an average diameter ranging from 60 to 80 nm. The resulting nanopatterned porous thin films demonstrate exceptional orderliness, as the pores are intricately designed by the cobalt ferrite grains, and the platinum substrate offers complete accessibility in the pore area. Our findings reveal high magnetization values, comparable to those of bulk CoFe2O4, in the dense film. Additionally, in the case of the nanopatterned porous film, we observed a distinctive contribution of perpendicular magnetization. This innovative approach holds great promise for advanced magnetization and thin‐film engineering applications. [ABSTRACT FROM AUTHOR]

In this work, we examine the formation of iron-based magnetic domains on two-dimensional (2D) single-crystal bismuth telluride plates. Using solvothermal chemical methods, 2D bismuth telluride (Bi2Te3) single crystalline nanoplates were reacted with iron salts (FeCl2) to achieve electrical doping. The use of a reducing agent [L(+)-ascorbic acid] along with FeCl2 resulted in homogeneous dispersion of iron across the crystal, whereas non-reduced iron doping achieved edge growth of iron/iron oxide nanoparticles. High-resolution analytical electron microscopy was used to examine the iron nanoparticle accumulation and morphology at nanoplate edges for non-reduced materials and iron dispersions within the crystals in the case of reduction. Our analysis revealed little variation in the atomic uptake of iron in any form over a range of solution-dopant concentrations. However, structural analysis and transport measurements clearly indicate the tendency of the dopant nanoparticles to oxidize quickly. The Seebeck coefficient and power factor also express modifications with exposure to oxidation, providing an indirect probe of the dopant modification to the host Bi2Te3's electronic properties. Importantly, however, magnetic force microscopy images show a distinct difference in the formation of magnetic phases with and without the use of reducing agents during iron doping. This suggests that oxidation post-doping does not form magnetic phases, whereas oxidation during the doping process is suitable for obtaining magnetically doped Bi2Te3 nanocrystals. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Protein‐protein interactions (PPIs) play a crucial role in drug discovery and disease treatment. However, the development of effective drugs targeting PPIs remains challenging due to limited methodologies for probing their spatiotemporal anisotropy. Here, we propose a single‐molecule approach using a unique force circuit to investigate PPI dynamics and anisotropy under mechanical forces. Unlike conventional techniques, this approach enables the manipulation and real‐time monitoring of individual proteins at specific amino acids with defined geometry, offering insights into molecular mechanisms at the single‐molecule level. The DNA force circuit was constructed using click chemistry conjugation methods and genetic code expansion techniques, facilitating orthogonal conjugation between proteins and nucleic acids. The SET domain of the MLL1 protein and the tail of histone H3 were used as a model system to demonstrate the application of the DNA force circuit. With the use of atomic force microscopy and magnetic tweezers, optimized assembly procedures were developed. The DNA force circuit provides an exceptional platform for studying the anisotropy of PPIs and holds promise for advancing drug discovery research targeted at PPIs. [ABSTRACT FROM AUTHOR]

Thin ferromagnet/heavy metal multilayer films are considered as prospective media for a magnetic recording and Co/Pd films are a good example of such materials. In this work, the magnetic properties and micromagnetic structure of Co/Pd multilayer films are studied with different bilayer thicknesses ([Co(0.3 × t nm)/Pd(0.5 × t nm)]10), but with the same ratio Co versus Pd. Transmission electron microscope and X‐ray diffraction studies allow authors to suppose that the investigated films are highly mixed alloys. Magnetic force microscopy and Lorentz transmission electron microscopy showed the presence of various micromagnetic features in the films. Along with skyrmions that are well‐known magnetic topological artifacts some new features are revealed, which are interpreted as 360° domain walls, skyrmioniums and the combination of the above two. It is found that the type and density of micromagnetic features strongly depend on the bilayer thickness parameter (t). The effect is associated with the peculiarities of interfacial magnetic interactions in the samples with highly mixed interfaces. The tooling coefficient represents a useful tool of the electron beam evaporation technique enabling wide manipulation of micromagnetic particles, in particular, skyrmioniums that are currently considered a prospective media for current driven magnetic recording. [ABSTRACT FROM AUTHOR]

The recent decade has seen a huge impact of nanotechnology in different sciences. In analytical chemistry, nanomaterials have been utilized for various purposes from sample preparation to detection. The impact of nanotechnology in analytical science is not limited to the improvement of analytical methodologies. Nanomaterials have been utilized for nanomaterials analysis as nanotools. Nanotools are used to investigate and work with materials at the nanoscale. Nanotechnology has also enabled new applications such as nanoscale tips used for topological microscopy in atomic force microscopy, scanning tunneling microscopy, and magnetic force microscopy. These techniques utilize nanotechnology to improve their efficiency. Furthermore, nanotechnology has enabled the construction of tweezers and robots in the nanoscale. These nano-enabled tools (nanotools) have been successfully utilized for nanoanalysis and nanomanipulation. Atomic force microscopy, scanning tunneling microscope, and magnetic force microscopy are not only meant to image nanostructured surfaces but also they are utilized for the manipulation of materials at the atomic and nanoscale. Nanotweezers, nanorobots, and laser tweezers using nanoapertures are also able to manipulate nano and microscale materials. This paper reviews the principles and application of the mentioned nano-enabled techniques as nanotools in analytical chemistry with a focus on nanomaterials nanoanalysis and nanomanipulation as nanoanalytes. [ABSTRACT FROM AUTHOR]

We present a study on the superconducting properties of 500 nm thick NbTiN films grown by reactive co-sputtering on silicon substrates at room temperature. The samples exhibit a chemical composition with Nb (50 at.%) and Ti (50 at.%), revealing a polycrystalline structure characterized by columnar growth and an average lateral grain size of approximately 40 nm. The superconducting critical temperature (Tc) was measured at 13.8 K, and the upper critical field extrapolated to zero temperature reached 22 T, resulting in a coherence length (ξ) of 3.8 nm. The penetration depth (λ) was determined through local magnetic force microscopy measurements conducted at temperatures of 4.25 and 6 K. The obtained values were 400 (15) nm at 4.25 K and 430 (15) nm at 6 K. Extrapolating these measurements to zero temperature, we obtained an estimated value of 380 nm. A comparison was made with samples that underwent thermal annealing at 700 °C, resulting in a reduction of disorder at the nanoscale and an increase in Tc to 14.2 K. Despite this enhancement, the coherence length ξ (0) remained at approximately 3.8 nm, with no appreciable changes in the λ values. Our findings contribute to understanding fundamental superconducting parameters in nitride thin films, with potential applications ranging from resonant accelerator cavities to Josephson junctions and radiation detectors. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: Protein‐protein interactions (PPIs) play a crucial role in drug discovery and disease treatment. However, the development of effective drugs targeting PPIs remains challenging due to limited methodologies for probing their spatiotemporal anisotropy. Here, we propose a single‐molecule approach using a unique force circuit to investigate PPI dynamics and anisotropy under mechanical forces. Unlike conventional techniques, this approach enables the manipulation and real‐time monitoring of individual proteins at specific amino acids with defined geometry, offering insights into molecular mechanisms at the single‐molecule level. The DNA force circuit was constructed using click chemistry conjugation methods and genetic code expansion techniques, facilitating orthogonal conjugation between proteins and nucleic acids. The SET domain of the MLL1 protein and the tail of histone H3 were used as a model system to demonstrate the application of the DNA force circuit. With the use of atomic force microscopy and magnetic tweezers, optimized assembly procedures were developed. The DNA force circuit provides an exceptional platform for studying the anisotropy of PPIs and holds promise for advancing drug discovery research targeted at PPIs. [ABSTRACT FROM AUTHOR]

Square planar nickel microparticles deposited on the surface of single crystals of lithium niobate in the hexagonal phase and potassium titanyl phosphate were studied. Because the thermal expansion coefficients of these single crystals strongly differ, the uniaxial anisotropy is induced in the microparticles by heating or cooling relative to the deposition temperature. The phenomenon of the induction of anisotropy was explored using magnetic force microscopy and ferromagnetic resonance spectroscopy. Data obtained from ferromagnetic resonance spectra show that, in the ensemble of microparticles, with increasing temperature of the samples from –10 to 60°C, the axis of anisotropy rotates by 90°. This agrees well with the data about the domain structure of an individual microparticle, obtained by magnetic force microscopy. [ABSTRACT FROM AUTHOR]

L10-FePt thin films with (111)-texture were deposited on Si(100) substrates at various atomic ratios and annealing temperatures to be used as a cover layer for magnetic force microscope (MFM) tips. Their microstructure and magnetic properties were systematically studied. The experimental results indicate that both atomic ratio and annealing temperature affect the disorder-order transformation of FePt films. In particular, when the atomic ratio approaches 1:1 (Fe: 51 at.%, Pt: 49 at.%) and the annealing temperature is 600 °C, the FePt film exhibits an ultra-high in-plane coercivity of 13.2 kOe. This is attributed to the formation of an L10-FePt phase with high order parameters. Based on the optimal preparation parameters, MFM tips were prepared by depositing FePt films on non-magnetic Si tips. Magnetic domain structures of magnetic tape and magnetic recording medium were successfully observed using these home-made FePt MFM tips. Therefore, the high coercivity L10-FePt films with (111)-texture prepared on Si substrates are expected to be potential materials for the fabrication of MFM tips. [ABSTRACT FROM AUTHOR]

Thermal heating process has been used, under a pressure of 10−7 mbar, to deposit thin films of cobalt onto monocrystalline silicon substrate. The incident beam strikes the substrates under normal incidence. The thickness ranges from 50 to 400 nm. To investigate the static magnetic properties, the hysteresis loops are performed by means of alternating gradient field magnetometer device. The zero-field magnetic structure has been investigated by magnetic force microscopy (MFM) technique, using a Veeco 3100 apparatus. MFM images reveal well-defined stripe patterns, mainly for the thickest films, which infer the dominance of the magnetocrystalline anisotropy. The easy magnetization axis lies within the plane of the film with a small component out-of-the plane for the thicker films. Coercivity evolution versus thickness follows a t−n Néel law, characteristic of Bloch domain wall motion. In addition, it was found that coercivity depends plainly on the surface roughness of the films. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) materials that combine ferromagnetic, semiconductor, and piezoelectric properties hold significant potential for both fundamental research and spin electronic devices. However, the majority of reported 2D ferromagnetic-semiconductor-piezoelectric materials rely on d-electron systems, which limits their practical applications due to a Curie temperature lower than room temperature (RT). Here, we report a high-crystallinity carbon nitride (CCN) material based on sp-electrons using a chemical vapor deposition strategy. CCN exhibits a band gap of 1.8 eV and has been confirmed to possess substantial in-plane and out-of-plane piezoelectricity. Moreover, we acquired clear evidences of ferromagnetic behavior at room temperature. Extensive structural characterizations combined with theoretical calculations reveal that incorporating structural oxygen into the highly ordered heptazine structure causes partial substitution of nitrogen sites, which is primarily responsible for generating room-temperature ferromagnetism and piezoelectricity. As a result, the strain in wrinkles can effectively modulate the domain behavior and piezoelectric potential at room temperature. The addition of RT ferromagnetic-semiconductor-piezoelectric material based on sp-electrons to the family of two-dimensional materials opens up numerous possibilities for novel applications in fundamental research and spin electronic devices. [ABSTRACT FROM AUTHOR]

The results of experimental studies and micromagnetic modeling of magnetic states in a one-dimensional array are presented. The array has the form of a chain of ferromagnetic disks coupled with a ferromagnetic nanowire made of the same material. The disks are located on opposite sides of the nanowire, which makes it possible to obtain distributions when the chiralities of the magnetic vortex shells in neighboring disks alternate, which can find application in vortex spin nanooscillators. By applying a magnetic field of an excited objective lens in situ and using Lorentz transmission electron microscopy, it is shown that in this system the chiralities of the shells of magnetic vortices can be controlled by magnetization in the sample plane along various azimuthal directions. When magnetized along the nanowire in disks located on opposite sides of it, vortex states with opposite chiralities are realized. An antivortex is formed in the nanowire itself at the boundary with the disk, since the local direction of magnetization in the wire and in the disk are anticollinear. When magnetized perpendicular to the nanowire, states with the same chirality are realized in all disks. In this case, two perpendicular domain walls are formed between the disks in the nanowire and the vortex in the disk is shifted to one of the edges along the nanowire. [ABSTRACT FROM AUTHOR]

Abstract The electronic orders in kagome materials have emerged as a fertile platform for studying exotic quantum states, and their intertwining with the unique kagome lattice geometry remains elusive. While various unconventional charge orders with broken symmetry is observed, the influence of kagome symmetry on magnetic order has so far not been directly observed. Here, using a high‐resolution magnetic force microscopy, it is, for the first time, observed a new lattice form of noncollinear spin textures in the kagome ferromagnet in zero magnetic field. Under the influence of the sixfold rotational symmetry of the kagome lattice, the spin textures are hexagonal in shape and can further form a honeycomb lattice structure. Subsequent thermal cycling measurements reveal that these spin textures transform into a non‐uniform in‐plane ferromagnetic ground state at low temperatures and can fully rebuild at elevated temperatures, showing a strong second‐order phase transition feature. Moreover, some out‐of‐plane magnetic moments persist at low temperatures, supporting the Kane–Mele scenario in explaining the emergence of the Dirac gap. The observations establish that the electronic properties, including both charge and spin orders, are strongly coupled with the kagome lattices.

Nanoscale analysis of magnetic properties of graphene nanoribbons (GNRs) conjugated with magnetic nanoparticles has been studied in this work. The effect of varying concentrations of Fe 3 O 4 and Ni nanoparticles on the magnetic domain structure of GNRs has been investigated using magnetic force microscopy (MFM). A variable external magnetic field was applied to the samples, and an evident variation in the domain structure with a change in the magnetic field was observed. It was found that magnetic properties and the imaged magnetic domain structure are influenced by the concentration of magnetic nanoparticles conjugated with GNRs. The vibrating sample magnetometry (VSM) studies support the nano-domain studies done using MFM such that the trend observed for the saturation magnetization obtained from vibrating sample magnetometry (VSM) matches that of the phase difference obtained using MFM. [ABSTRACT FROM AUTHOR]

Room-temperature magnetoelectric multiferroicity has been observed in c-axis oriented GaFeO3 thin films (space group P n a 2 1), grown on economic and technologically important (100)Si substrates by a pulsed laser deposition technique. Structural analysis and comprehensive mapping of the Ga:Fe ratio across a length scale range of 104 reveals coexistence of epitaxial and chemical strain. It induces formation of finer magnetic domains and large magnetoelectric coupling—a decrease in remanent polarization by ∼ 21 % under ∼ 50 kOe. Magnetic force microscopy reveals the presence of both finer (< 100 nm) and coarser (∼ 2 μ m) magnetic domains. Strong multiferroicity in epitaxial GaFeO3 thin films, grown on a (100)Si substrate, brighten the prospect of their integration with Si-based electronics and could pave the way for development of economic and more efficient electromechanical, electrooptic, or magnetoelectric sensor devices. [ABSTRACT FROM AUTHOR]

Fe–Ga alloys, containing 18, 21, and 23 at.% of Ga, were prepared in bulk form. In their as-cast state, they display a small magnetostriction, that is strongly improved after annealing at 1000 ° C for 24 h, and subsequent rapid cooling. Multiple characterization techniques, such as x-ray diffraction, differential scanning calorimetry, Mössbauer spectroscopy, temperature-dependent magnetization curves, hysteresis loops, magnetic force microscopy, and magnetostriction measurements, were exploited in synergy to gain a deep understanding of the structure–property relationships in the studied alloys, before and after annealing. The A2 phase, which is favored in the lower range of compositions and is promoted at the expense of the D 0 3 one by annealing, is responsible for characteristic dendritic and maze magnetic domains, and for the strong improvement of the magnetostriction, which almost reaches 240 ppm (transverse configuration) in the alloys with 18 at.% of Ga, after annealing. [ABSTRACT FROM AUTHOR]

The features of magnetic microstructure of La0.73Dy0.27Mn2Si2 at 293 K have been visualized by atomic force and magnetic force microscopy. Magnetic force images reveal the presence of low-contrast magnetic domains. The change of Raman spectral characteristics of light scattering in the process of cooling La0.73Dy0.27Mn2Si2 to a temperature of 263 K is experimentally detected. The electronic structure of La0.73Dy0.27Mn2Si2 is investigated by resonance photoemission spectroscopy with the use of the synchrotron radiation. Resonances at the 3d and 4d levels of electronic structure show different properties of valence electrons. Using the Dy 3d–4f (M4.5 absorption edge) resonance, the distribution of 4f states of dysprosium in the valence band is determined. Photoemission upon the giant Dy 4d–4f (N4.5 absorption edge) resonance is determined by the contribution of all states in the valence band due to the sudden involvement of the Coulomb interaction. The energies of the 5p and 4f levels of La, the 4f level of Dy, and the 3d level of Mn in the valence band are determined. [ABSTRACT FROM AUTHOR]

Structure, surface morphology, and magnetic properties of Sr0.6Ba0.4Nb2O6 film and BiFeO3/Sr0.6Ba0.4Nb2O6 heterostructures with different BiFeO3 thicknesses were studied. The heterostructures were fabricated by RF-cathode sputtering on a SrRuO3/MgO(001) substrate. According to X-ray diffraction data for BiFeO3/Sr0.6Ba0.4Nb2O6/SrRuO3/MgO(001), the BiFeO3 layer had a tensile strain of the unit cell up to 0.43%. Atomic force microscopy showed that the surface of the heterostructures had a low roughness and was represented by growth blocks, the average size of which did not exceed 91 nm. The results of magnetic force microscopy showed a clear magnetic response in BiFeO3/Sr0.6Ba0.4Nb2O6/SrRuO3/MgO(001) heterostructures for 30-150 nm thick BiFeO3 layer. [ABSTRACT FROM AUTHOR]

When bores with high length-to-diameter ratios (l/D > 10) and large diameters (D > 40 mm) are required, usually, the Boring and Trepanning Association (BTA) deep hole drilling process is used. Common industrial applications of this process are aerospace engineering and petrol exploration, where drilled components range from landing gears and engine shafts to drill collars. Since such parts tend to be particularly costly and highly safety–critical, ensuring favorable surface integrity during drilling is crucial to guarantee their reliability and performance. This study aims to identify correlations between the BTA deep hole drilling process and the resulting surface integrity using experimental and simulative approaches. The impact of feed and cutting speed on the thermomechanical loads and the resulting surface integrity are analyzed, also taking into account the occurrence of dynamic process disturbances. Particularly, the formation of white etching layers (WEL) is investigated using well-established, conventional techniques such as optical microscopy and microhardness testing. Additionally, innovative micromagnetic methods are employed. Magnetic Barkhausen noise (MBN) analysis is qualified as a well-applicable approach for rapid, non-destructive detection of WEL. To enhance understanding of MBN analysis and increase its robustness, the underlying mechanisms, governing the magnetic behavior of the subsurface are elucidated in detail by X-ray diffraction (XRD), electron backscatter diffraction (EBSD), magnetic force microscopy (MFM) and magneto-optical Kerr effect (MOKE) microscopy. The methodology will serve as a basis for controlled subsurface conditioning in BTA deep hole drilling. [ABSTRACT FROM AUTHOR]

We present a study on the magnetic domain configuration in the van der Waals ferromagnet CrGeTe3 using a vector-field cryogenic magnetic force microscopy. Our investigation demonstrates the influence of magnetic fields strength and angle on the magnetic domain configuration, showing the coexistence of striped and spike-like magnetic domains. This study contributes to understanding the impact of uniaxial magnetic anisotropy on the domain configuration of van der Waals ferromagnets, offering insights into stabilizing different domain patterns. [ABSTRACT FROM AUTHOR]

Magnetic monopole motion (without its partner in a pair) as a function of external magnetic fields is presented as a fingerprint of freedom of these emergent quasi-particles in a two-dimensional artificial spin ice material. Such freedom, required, for example, for further application in magnetricity, is only possible due to ground-state degeneracy, which causes an anisotropic string energy reduction in rectangular ice geometries, designed to allow highest equidistance among lateral and diagonal neighbor nanomagnets. By measurements of magnetic force microscopy, we observe magnetic monopole creation, transport, and annihilation in such an arrangement, where monopoles are free to move throughout large regions of the sample, since they are not permanently bound by the string bonds, as commonly observed in conventional artificial spin ice systems. Instead, monopoles leave a wake of elongated tensionless string, which is connected to superficial charges or charges pinned to the array borders. [ABSTRACT FROM AUTHOR]

The resistive switching effect in individual ferromagnetic filaments in memristive stacks based on ZrO2(Y)/Ni functional layers was studied experimentally. A conductive probe of an atomic force microscope played a role of a movable top electrode of a virtual memristive stack. The features of bipolar-type resistive switching found were related to the rapture and restoring of the filaments containing Ni atoms in the ZrO2(Y) dielectric films and are probably caused by different degree of metallization of the filaments. The filaments fromed were manifested in the images obtained by magnetic force microscopy as single-domain ferromagnetic particles. [ABSTRACT FROM AUTHOR]

In this article, the results of incremental analysis on the thickness, aspect ratio, and crystallographic substrate orientation dependence of magnetic domain formation in CoFe nanolayer patterns (NPs) on GaAs (001) substrates by magnetic force microscopy are reported. All the 35 nm thick CoFe NPs show multiple magnetic domains under as‐deposition condition whereas the 13 nm thick CoFe NPs have a single magnetic domain in the case of the patterns with a relatively small size and high aspect ratio. Subsequently, the magnetic fields are applied in the direction parallel to the <110> and <1–10> directions of the substrates to analyze a magnetization switching behavior in the patterns. The results reveal that the magnetic fields required for magnetization switching markedly tend to increase, with decreasing the thickness of the patterns and increasing their aspect ratio. A general tendency is obtained, which a higher magnetic field is needed for a higher aspect ratio and a thinner thickness of the NPs. Even in the case of the patterns with an aspect ratio of unity and a thickness of 35 nm (but, a smaller size), a single magnetic domain is formed at a relatively high applied magnetic field of 1500 Gauss. [ABSTRACT FROM AUTHOR]

To obtain high-resolution magnetic force microscopy (MFM) images, it is essential to have a cantilever with a high-quality factor. However, conventional vibrating cantilevers typically have quality factor values in the range of a few hundred, which limits their sensitivity for MFM measurements. To address this limitation, numerous studies have explored methods to enhance the quality factor in different environments, including vacuum, air, and liquid. This study introduces a novel approach for improving the quality factor using flowing helium gas. By selecting helium gas with a low viscosity coefficient, we successfully achieved a higher quality factor (Q-factor) of MFM microcantilever oscillations at room temperature in one atmosphere compared with the Q-factor in air. This provides a potential approach for achieving high-resolution MFM measurements under room temperature conditions. By optimizing the gas flow rate at room temperature in one atmosphere, we successfully obtained a higher MFM cantilever oscillation Q-factor and clearer MFM images compared with the air. The experimental results revealed a long and narrow resonant curve, and the quality factor significantly increased to 778.2, which is 3.8 times higher than that observed in air 205.4. Furthermore, systematic investigations demonstrated the capability of this approach to produce high-resolution MFM images of videotape track patterns under the optimized helium gas flow rate of 60 mm/s. [ABSTRACT FROM AUTHOR]

Effective control of domain walls or magnetic textures in antiferromagnets promises to enable robust, fast, and nonvolatile memories. The lack of net magnetic moment in antiferromagnets implies the need for creative ways to achieve such a manipulation. We conducted a study to investigate changes in magnetic force microscopy (MFM) imaging and in the magnon-related mode in Raman spectroscopy of virgin NiO films under a microwave pump. After MFM and Raman studies were conducted, a combined action of broadband microwave (0.01–20 GHz, power scanned from − 20 to 5 dBm) and magnetic field (up to 3 kOe) were applied to virgin epitaxial (111) NiO and (100) NiO films grown on (0001) Al 2 O 3 and (100) MgO substrates, following which the MFM and Raman studies were repeated. We observed a suppression of the magnon-related Raman mode subsequent to the microwave exposure. Based on MFM imaging, this effect appeared to be caused by the suppression of large antiferromagnetic domain walls due to the possible excitation of antiferromagnetic spin oscillations localized within the antiferromagnetic domain walls. [ABSTRACT FROM AUTHOR]

Raman spectra of the LaMn2Si2 compound were obtained for the first time by Raman spectroscopy. The change in the Raman spectral characteristics in the temperature range of 263–553 K was investigated. The high sensitivity of the Raman spectroscopy method to a change in the magnetic state caused by a temperature influence has been determined. A change in the spectral characteristics of the vibration mode of manganese atoms near the Curie and Neel temperatures has been revealed. The magnetic force microscopy technique was used to investigate the surface features of the LaMn2Si2 compound at room temperature. A change in the type of magnetic domain structure in LaMn2Si2 after cooling from 298 to 263 K has been found. [ABSTRACT FROM AUTHOR]

Abstract We present a novel method for fabricating dense and nanopatterned porous cobalt ferrite (CoFe2O4) thin films with a remarkable thickness of 65 nm, achieved through direct block copolymer self‐assembly. By decomposing the block copolymer and inducing crystallization of the spinel phase, we successfully produce films exhibiting quasi‐hexagonal arrays of pores with an average diameter ranging from 60 to 80 nm. The resulting nanopatterned porous thin films demonstrate exceptional orderliness, as the pores are intricately designed by the cobalt ferrite grains, and the platinum substrate offers complete accessibility in the pore area. Our findings reveal high magnetization values, comparable to those of bulk CoFe2O4, in the dense film. Additionally, in the case of the nanopatterned porous film, we observed a distinctive contribution of perpendicular magnetization. This innovative approach holds great promise for advanced magnetization and thin‐film engineering applications.

Analysis of properties related to spin textures, such as the magnetic vortex state, is mainly based on spin configuration data, which is directly related to magnetic parameters involved in the system's Hamiltonian. Here, we focus on magnetic parameter estimation by implementing the machine learning (ML) approach, especially on magnetic force microscopy (MFM) images of vortex states within nanodots generated by micromagnetic simulation. The exchange constant Aex and saturation magnetization Ms as well as exchange length as a reduced parameter Lex(Aex, Ms) are estimated by different convolutional neural network (CNN) models. We also evaluated the CNN models, trained on simulated MFM images with non-zero temperature, on a reference experimental MFM image and found the performance to a satisfactory level of accuracy. Moreover, the same CNN models, trained for binary classification of vortex states based on helicity from MFM images, successfully identified the vortex helicity from simulated as well as experimental MFM images. These findings show the possible application of ML in magnetic parameter estimation and the analysis of magnetic vortex states simply with images obtained from this commonly used imaging technique that is significant in efficient investigation of material properties based on intrinsic parameters for spintronic device applications. [ABSTRACT FROM AUTHOR]

We have studied theoretically magnetic resonance force microscopy with a high-frequency nanomechanical cantilever when the cantilever frequency matches the resonant frequency of a single electron spin. Our analysis shows that in this situation, there is a small probability that the cantilever will oscillate with a large frequency shift. This can open new experimental opportunities for increasing the sensitivity in the detection of a single electron spin or even a single nuclear spin by using a high-frequency cantilever. [ABSTRACT FROM AUTHOR]

Artificial spin-ice systems are patterned arrays of magnetic nanoislands arranged into frustrated geometries and provide insight into the physics of ordering and emergence. The majority of these systems have been realized in two-dimensions, mainly due to the ease of fabrication, but with recent developments in advanced nanolithography, three-dimensional artificial spin ice (ASI) structures have become possible, providing a new paradigm in their study. Such artificially engineered 3D systems provide new opportunities in realizing tunable ground states, new domain wall topologies, monopole propagation, and advanced device concepts, such as magnetic racetrack memory. Direct imaging of 3DASI structures with magnetic force microscopy has thus far been key to probing the physics of these systems but is limited in both the depth of measurement and resolution, ultimately restricting measurement to the uppermost layers of the system. In this work, a method is developed to fabricate 3DASI lattices over an aperture using two-photon lithography, thermal evaporation, and oxygen plasma exposure, allowing the probe of element-specific structural and magnetic information using soft x-ray microscopy with x-ray magnetic circular dichroism (XMCD) as magnetic contrast. The suspended polymer–permalloy lattices are found to be stable under repeated soft x-ray exposure. Analysis of the x-ray absorption signal allows the complex cross section of the magnetic nanowires to be reconstructed and demonstrates a crescent-shaped geometry. Measurement of the XMCD images after the application of an in-plane field suggests a decrease in magnetic moment on the lattice surface due to oxidation, while a measurable signal is retained on sub-lattices below the surface. [ABSTRACT FROM AUTHOR]

Magnetic anisotropy is an important character for magnetic materials. In this work, magnetic anisotropy of (110)-oriented ferrimagnetic NiCo2O4 (NCO) thin films deposited epitaxially on MgAl2O4 substrates by pulsed laser deposition is studied and compared with (001)-oriented NCO films. While the (001)-oriented films show a perpendicular magnetic anisotropy with the out-of-plane [001] direction as the magnetic easy axis, a jump in magnetic hysteresis loop is observed for the (110)-oriented films with a field applied vertically along the out-of-plane [110] direction. This jump in hysteresis loop is associated with a spin reorientation transition, depending on the applied field and temperature. Magnetic force microscopy reveals that this spin reorientation develops as domains nucleate, grow, and coalesce. This spin reorientation transition is discussed in terms of the competition between different magnetic anisotropy in an external field. [ABSTRACT FROM AUTHOR]

A detailed study of the coherent spin dynamics of photoexcited carriers in a heterostructure with an InGaAs/GaAs quantum well and a δ-Mn-layer separated from the quantum well by a 3–10 nm-thick GaAs spacer indicates its strong non-uniformity in the plane and mesoscopic separation to the regions of carrier localization. Mesoscopic separation with a characteristic scale of ~100–200 nm is also observed using magnetic force microscopy below the Curie temperature of the δ-Mn-layer. [ABSTRACT FROM AUTHOR]

Recently, the development of long-range electric vehicles with effective electric motors has drawn considerable attention. The key to achieving such electric vehicles development is power saving, which has served as an essential motive for development of new magnetic materials. In this regard, further improvement of magnetic materials requires deep insight into the existence of eddy currents, which are primary contributors toward power loss in practical applications. Therefore, exploring the key effects of eddy currents on overall magnetic properties is essential. Here, we demonstrate clearly distinguished eddy current distributions being influenced by local magnetic properties via multidimensional magnetic force microscopy. Using our model systems, we explored the key role of an insulation layer and magnetic domains on eddy current dependent magnetic properties. In particular, we visualized the correlation between the eddy current and magnetic domain/domain wall. Therefore, our approach provides detailed characterization of eddy current, particularly related to the underlying contributions of local magnetic properties, offering crucial insights for improvement of electric motors. [ABSTRACT FROM AUTHOR]

The bulk, pristine sp2 carbons, such as graphite, carbon nanotubes, and graphene, are usually assumed to be typical diamagnetic materials. However, over the past two decades, there have been many reports about the ferromagnetism in these sp2 carbon materials, which have attracted intense interest for basic research and potential applications. In this review, we focus on the evidence and developments of the emergent ferromagnetism in sp2 carbon revealed by nine kinds of experimental methods: magnetic force microscopy (MFM), magnetization measurements with physical property measurement system (PPMS), X-ray magnetic circular dichroism (XMCD), scanning tunneling microscopy (STM), miniaturized magnetic particle inspection (MPI), anomalous Hall effect (AHE), mechanical deflection of carbon nanotube cantilevers, magnetoresistance, and spin-related devices (spin field effect transistor and spin memory). The advantages, conclusions, challenges, and future of these methods are discussed. The ferromagnetism in sp2 carbon will open a door to explore exotic physical phenomena and lay the basis for the development of integrated circuit of spintronics, which is fundamentally different from charge-based conventional electronics. [ABSTRACT FROM AUTHOR]