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Achieving spin current switching functionality is crucial for the development next-generation low power information storage. In this study, the spin reorientation and temperature dependence of spin Hall angle θSH in the Permalloy (Py)/Pd bilayer were investigated by using ferromagnetic resonance, spin pumping, inverse spin Hall effect, and quantum interference transport. The uniaxial ferromagnetic perpendicular magnetic anisotropy (PMA) induced by spin reorientation persists at the Py/Pd interface below 30 K. This PMA further enhances the interfacial spin scattering, leading to a reduction of injected spin current, as indicated by the underestimated θSH values. These experimental results demonstrate that the interfacial spin reorientation at the ferromagnet/heavy metal interface, commonly employed in spintronic devices, causes a significant spin memory loss effect. Our findings provide valuable insights into the influence of interlayer spin configuration on spin transport, which can be utilized in the rational design of spintronic devices based on pure spin current. [ABSTRACT FROM AUTHOR]

The performance of iron-based superconductors in high magnetic fields plays an important role for their practical application. In this work, we measured the magnetostriction and magnetization of BaFe1.908Ni0.092As2 single crystals using pulsed magnetic fields up to 60 T and static magnetic fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the order of 10–4) was observed in the direction of twin boundaries. The magnetization measurements evidence a high critical-current density due to strong bulk pinning. By using magnetization data with an exponential flux-pinning model, we can reproduce the magnetostriction curves qualitatively. This result shows that the magnetostriction of BaFe1.908Ni0.092As2 can be well explained by a flux-pinning-induced mechanism. [ABSTRACT FROM AUTHOR]

Excitation using surface acoustic waves (SAW) has demonstrated efficacy in improving microscale particle/chemical transport due to its ability to generate microscale wavelengths. However, the effects of acoustic stimulation on transport processes along the length of sub-wavelength microchannels and their underlying mechanisms, essential for long-range transport, have not been examined in detail. In this work, we investigate diffusion along the length of subwavelength microchannels using experimental and simulation approaches, demonstrating enhanced transport under SAW excitation. The microchannel-based enhanced diffusion mechanisms are further studied by investigating the acoustic pressure and streaming fields, finding that the degree of enhancement is a function of applied power, microchannel dimensions, and viscosity. This microchannel-based diffusion enhancement approach is applicable to microfluidic and biomedical microscale transport enhancement, with the findings here being relevant to acoustic-based micro-mixing and neurodegenerative therapies. [ABSTRACT FROM AUTHOR]

A chiral soliton lattice (CSL) is a topological spin-texture that has potential applications in next-generation spintronic devices. In this work, we performed angle-dependence of magnetization and electron spin resonance (ESR) investigations on the CSL host Yb(Ni1−xCux)3Al9 with x = 0.06 (YNCA). The angle-dependent magnetization reveals a peculiar variable magnetic anisotropy. The maximum magnetization axis is parallel to the ab-plane below the field of ∼35.7 kOe while shifts to the c-axis at higher fields. The microwave responses of the CSL helicoid and ferromagnetic resonance (FMR) of the forced ferromagnetic state (FFM) are observed and appear as two resonance lines on ESR spectra with the highest intensities in the ab-plane. When the external field is rotated from H ⊥ c to H / / c , the resonance field H r 1 corresponding to the CSL helicoid decreases while H r 2 correlated with the FMR increases. Furthermore, the temperature-dependent ESR shows that the CSL persists until 15 K much higher than TC (6.4 K), which suggests a precursor phenomenon. The microwave response in YNCA provides a powerful tool for modulating and researching the CSL. [ABSTRACT FROM AUTHOR]

Many studies have established a major effect of nanoscale confinement on the glass transition temperature (Tg) of polystyrene (PS), most commonly in thin films with one or two free surfaces. Here, we characterize smaller yet significant intrinsic size effects (in the absence of free surfaces or significant attractive polymer-substrate interactions) on the Tg and fragility of PS. Melt infiltration of various molecular weights (MWs) of PS into anodic aluminum oxide (AAO) templates is used to create nanorods supported on AAO with rod diameter (d) ranging from 24 to 210 nm. The Tg (both as Tg,onset and fictive temperature) and fragility values are characterized by differential scanning calorimetry. No intrinsic size effect is observed for 30 kg/mol PS in template-supported nanorods with d = 24 nm. However, effects on Tg are present for PS nanorods with Mn and Mw = 175 kg/mol, with effects increasing in magnitude with increasing MW. For example, in 24-nm-diameter template-supported nanorods, Tg,rod - Tg,bulk = -2.0 to -2.5 °C for PS with Mn = 175 kg/mol and Mw = 182 kg/mol, and Tg,rod Tg,bulk = ~-8 °C for PS with Mn = 929 kg/mol and Mw = 1420 kg/mol. In general, reductions in Tg occur when d ≤ ; -2Rg, where Rg is the bulk polymer radius of gyration. Thus, intrinsic size effects are significant when the rod diameter is smaller than the diameter (2Rg) associated with the spherical volume pervaded by coils in bulk. We hypothesize that the Tg reduction occurs when chain segment packing frustration is sufficiently perturbed by confinement in the nanorods. This explanation is supported by observed reductions in fragility with the increasing extent of confinement. We also explain why these small intrinsic size effects do not contradict reports that the Tg-confinement effect in supported PS films with one free surface exhibits little or no MW dependence. [ABSTRACT FROM AUTHOR]

The pressure dependence of the band gap energy of the dilute nitride GaNP is analyzed. It is found that the pressure dependence of the Γ conduction band minimum (CBM) is stronger than that of the X CBM. We also find that the energy difference between the X CBM and the Γ CBM in GaNP becomes large with increasing N content. In order to describe the pressure dependence of the band gap energy of the dilute nitride GaNP, a model is developed. Based on the model, we obtain the energy difference between the X CBM and the Γ CBM in GaNP at standard atmospheric pressure. It agrees well with the results obtained by other method. [ABSTRACT FROM AUTHOR]

While charge-ordering transition is well established in the oxygen-deficient layered cobaltite YBaCo2O5, there has been no evidence for the transition in the analogous compound GdBaCo2O5 either from neutron diffraction or from magnetic susceptibility experiments. In this paper, we present comparative studies on the electron spin resonance (ESR) of Gd3+ ions in Y1-xGdxBaCo2O5 (x = 0.01, 0.25, and 1) polycrystalline samples. Magnetic susceptibility was also performed for comparison with the ESR results. It was found that charge-ordering transition for Y0.75Gd0.25BaCo2O5 revealed by the susceptibility is also manifested in the characters of the ESR data. The similar temperature-evolution of the ESR parameters for GdBaCo2O5 provides a support for the existence of charge-ordering transition, although no characteristic of the transition is evidenced from susceptibility experiments, which can be understood as being hidden by dominant paramagnetism of Gd3+ ions in this compound. We have interpreted the temperature variation of ESR parameters in terms of electron localization associated with Co2+/Co3+ charge ordering. [ABSTRACT FROM AUTHOR]

Chiral magnetic soliton (CMS), an isolated topological kink consisting of spins, has potential applications in spintronics. In this work, the microwave response of layered MnNb3S6, which is suggested as a candidate for CMS, is investigated by the electronic spin resonance (ESR). Angle-dependent ESR spectra show that the microwave response is strong for H ⊥ c while it is weak for H / / c , where c is the c-axis of the single crystal. When H ⊥ c , two resonance lines are observed, which are marked as H r 1 for the higher field and H r 2 for the lower field. It is determined that H r 1 originates from the ferromagnetic resonance of forced ferromagnetic moments, which evolves into paramagnetic resonance above TC. Meanwhile, H r 2 existing only below TC fulfills the Goldstone excitation of CMS. The microwave response of MnNb3S6 supports the existence of CMS in MnNb3S6, and is proved to be an effective means for modulating and investigating CMS. [ABSTRACT FROM AUTHOR]

Electric current induced Joule heating effects have been investigated in La0.8Ba0.2MnO3 ultrathin films deposited on a LaAlO3(001) single crystal substrate with a smaller lattice constant by using the sol–gel method. By applying moderate bias currents (∼10 mA), it is found that Joule self-heating simply gives rise to a temperature deviation between the thermostat and the test sample, but the intrinsic ρ(T) relationship measured at a low current (0.1 mA) changes a little. However, it is noteworthy that the low-temperature transport behavior degrades from the metallic to the insulating state after applying higher bias currents (>31 mA) in vacuum. Furthermore, the metallic transport can be recovered by placing the degraded film in air. The results clearly suggest that the oxygen vacancy in the La0.8Ba0.2MnO3 films is controllable in different atmospheres, particularly with the aid of the Joule self-heating. According to the SEM images, we attribute the controlled oxygen vacancy to the nano-sized labyrinth pattern of the films, where the large surface-to-volume ratio plays a crucial role. [ABSTRACT FROM AUTHOR]

Co3Sn2S2, a quasi-two-dimensional system with a kagome lattice, has been found to be a magnetic Weyl semimetal recently. In this work, the anisotropies of magnetization and transport properties of Co3Sn2S2 were investigated. The high field measurements reveal a giant magnetocrystalline anisotropy with an out-of-plane saturation field of 0.9 kOe and an in-plane saturation field of 230 kOe at 2 K, showing a magnetocrystalline anisotropy coefficient Ku up to 8.3 × 105 J m−3, which indicates that it is extremely difficult to align the small moment of 0.29 μB/Co on the kagome lattice from the c axis to the ab plane. The out-of-plane angular dependence of Hall conductivity further reveals strong anisotropies in the Berry curvature and ferromagnetism, and the vector directions of both are always parallel with each other. For the in-plane situation, the longitudinal and transverse measurements for both I // a and I ⊥ a cases show that the transport on the kagome lattice is isotropic. These results provide the essential understanding of the magnetization and transport behaviors for the magnetic Weyl semimetal, Co3Sn2S2. [ABSTRACT FROM AUTHOR]

The magnetic and electronic transport properties of the lightly doped SrRu1-x Fex O3 (x ≤ 0.15) have been studied. All the samples show a paramagnetic-ferromagnetic phase transition and hysteresis effect. With the increase of Fe, the temperature of magnetic phase transition decreases but coercive field increases indicting the existence of antiferromagnetic interaction and magnetic-crystalline anisotropy. In low temperature, all the doping samples exhibit an insulating behavior while metal feature appears only at x ≤ 0.10 samples. The induced disorder suppresses the itinerant property of Ru 4d electron due to Fe random occupation. As a result, the ferromagnetism is weakened and metal-insulator transition is suppressed. [ABSTRACT FROM AUTHOR]

Spin relaxation properties of π-conjugated organic semiconductors are key indicators of the performance of organic spintronic devices. However, reliable determination of spin relaxation parameters in organic materials is hindered by complex interfacial phenomena at organic/ferromagnetic metal interfaces that couple spin injection with charge injection. Here, we study the spin pumping induced pure spin transport in Permalloy/rubrene/Pt trilayers and determine the spin diffusion length λs= 132 ± 9 nm and the spin relaxation time τs = 3.8 ± 0.5 ms in rubrene films at room temperature by using the inverse spin Hall effect. The determined spin diffusion length λs is found to be almost two times larger than that of ∼46.3 nm at 100 K extracted from rubrene spin valve devices in which charge carrier injection/detection occurs at organic/ferromagnetic metal interfaces. Our results demonstrate experimentally that the efficiency and the rate of spin polarized charge transport through the organic/ferromagnetic metal interface play a dominant role in determining the spin relaxation process of spin valve devices in which charge and spin currents are coupled. [ABSTRACT FROM AUTHOR]

We have studied the effect of the out-of-plane lattice on tensile strained (001) La0.7Ca0.3MnO3 thin films. The films were deposited on SrTiO3 substrates through magnetron sputtering technique under different Ar/O2/He gas flow ratios, varying the out-of-plane lattice from 3.823 Å to 3.845Å, which corresponds to an increase in the metal-insulator transition temperature. These changes are reversible after high-temperature anneal due to a massive helium release from the films occurring at temperatures around 540°C. The dependence of the transition temperature on lattice distortion is in good agreement with the prediction proposed by Millis et al. [J. Appl. Phys. 83, 1588 (1998)]. Considering the Jahn-Teller distortion enhanced by the in-plane biaxial strain in the films, we attribute the elevated transition temperature to the distortion relaxation due to He doping in the tensile strained films. The effective He doping by magnetron sputtering technique provides a simple strategy for manipulating functionality of oxide films. [ABSTRACT FROM AUTHOR]

Zn1−xMnxO nanorods and Zn1−2xMnxLixO nano-particles were synthesized by solvothermal method at 160 °C. X-ray diffraction and Raman results showed that Mn ions were well incorporated into the ZnO matrix. No magnetic hysteresis were found in the magnetization curves. The hyperfine structures were observed in electron spin resonance spectra, indicating no ferromagnetic interaction between substituted Mn ions. The co-doping of Li can only change the morphology not the magnetic properties. [ABSTRACT FROM AUTHOR]

One method of calculating critical exponents based on the field dependence on magnetic entropy change was applied to study critical behavior in Pr0.55Sr0.45MnO3. By using the obtained critical exponents, the modified Arrott plot [A. Arrott and J. E. Noakes, Phys. Rev. Lett. 19, 786 (1967)] is consistent with that by using conventional method. The calculated critical exponents not only obey the scaling theory, but also inosculate the deduced results from the Kouvel-Fisher method [J. S. Kouvel and M. E. Fisher, Phys. Rev. 136, A1626 (1964)]. It eliminates the drawback due to utilization of multistep nonlinear fitting in a conventional manner. Therefore, this means can be applied to investigate critical behavior. [ABSTRACT FROM AUTHOR]

Hybrid pulse laser deposition and liquid phase epitaxy methods have been used to produce in-plane c-axis (IPCA) oriented barium ferrite (BaM) films on a-plane (1120) sapphire substrates with low microwave loss and a high remanence. Total thicknesses were from 5 to 20 μm. A reasonable compromise for low loss and high remanence was reached at a thickness of 7 μm, with a remanence ratio of 0.84 and a 59 GHz peak-to-peak derivative linewidth of 250 Oe. The 20 μm thick film had a linewidth of 110 Oe, one of the smallest values ever obtained for IPCA BaM films. [ABSTRACT FROM AUTHOR]

The 9.41 GHz ferromagnetic resonance field and linewidth have been measured as a function of the angle (θH) between the external magnetic field and film normal for a series of 17.5 nm thick Co–Cr–Pt alloy films. The linewidths ranged from hundreds of Oersted to kiloersted, with different values at θH=0 and θH=90° and additional minima and maxima for θH-values from 16° to 64°. The profiles can be fitted with a combination of inhomogeneity line broadening, grain boundary two magnon scattering, and magnon-electron (m-e) scattering processes, with a notably small Gilbert damping α-value of 0.004 for the m-e term. [ABSTRACT FROM AUTHOR]

Publisher's Note: "On the anisotropies of magnetization and electronic transport of magnetic Weyl semimetal Co3Sn2S2" [Appl. Phys. This article was originally published online on 22 November 2019 with minor grammatical errors. All online versions of the article were corrected on 25 November 2019; the article is correct as it appears in the printed version of the journal. [Extracted from the article]

The magnetic states of the BaFe2-xCoxAs2 single crystal samples have been studied by magnetization and electron spin resonance measurements. We find a transformation of the Fe2+ spin state from high temperature high-spin state to low temperature low-spin state, indicating a small crystal field splitting energy. In the superconducting samples, both the magnetization and electron spin resonance results suggest an itinerant behavior of the system. [ABSTRACT FROM AUTHOR]

We have studied the magnetotransport properties of the La[sub l.4]Sr[sub l.6-y]Ba[sub y]Mn[sub 2]O[sub 7] (y≤0.50) samples with a bilayered perovskite structure. For lightly doped samples, the metal-insulator transition accompanying a three-dimensional ferromagnetic transition can be understood commonly in terms of the double-exchange interaction. For heavier doped samples, the metal-insulator transition remains without a ferromagnetic transition and shifts to higher temperature with increasing Ba doping level. On account of the coexistence of short-range ferromagnetic ordering and paramagnetic state, the results can be explained by a recent percolation model based on phase separation. The percolative metal-insulator transition is consistent with the relative ferromagnetic metallic fraction change with temperature and doping level. [ABSTRACT FROM AUTHOR]

We have studied the effects of Cr substitution in the perovskite La[sub 0.67]Sr[sub 0.33]MnO[sub 3] on the magnetic, electrical transport, and magnetoresistance properties. Cluster glass behaviors have been observed in the La[sub 0.67]Sr[sub 0.33]Mn[sub 1-x]Cr[sub x]O[sub 3] system. The most interesting feature is that extraordinary transport and colossal magnetoresistance (CMR) behaviors, characterized by double peaks, were observed with Cr substitution. When 0.1≤x≤0.2, the temperature range of CMR response is greatly broadened, from the lowest temperature to above room temperature. These results suggest that Cr substitution can be a potent way in tuning CMR response and also imply a ferromagnetic interaction similar to double exchange occurs between Mn and Cr. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The performance of iron-based superconductors in high magnetic fields plays an important role for their practical application. In this work, we measured the magnetostriction and magnetization of BaFe1.908Ni0.092As2 single crystals using pulsed magnetic fields up to 60 T and static magnetic fields up to 33 T, respectively. A huge longitudinal magnetostriction (of the order of 10–4) was observed in the direction of twin boundaries. The magnetization measurements evidence a high critical-current density due to strong bulk pinning. By using magnetization data with an exponential flux-pinning model, we can reproduce the magnetostriction curves qualitatively. This result shows that the magnetostriction of BaFe1.908Ni0.092As2 can be well explained by a flux-pinning-induced mechanism. [ABSTRACT FROM AUTHOR]

We have studied the magnetic and magnetotransport properties of the perovskite LaMn[sub 1-x]Cu[sub x]O[sub 3] (x≤0.3). All of these compounds show ferromagnetism and cluster glass behavior at low temperatures. Though no metallic-insulating transition associated with the ferromagnetic-paramagnetic transition appears, a large magnetoresistance was observed in the ferromagnetic phase. Due to the fact that the Cu ion in these compounds is divalent, the ferromagnetism in LaMn[sub 1-x]Cu[sub x]O[sub 3] is believed to be consistent with the Mn[sup 3+]-O-Mn[sup 4+] double-exchange mechanism. These results suggest that double exchange and large magnetoresistance can be obtained by direct Mn-site doping. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A chiral soliton lattice (CSL) is a topological spin-texture that has potential applications in next-generation spintronic devices. In this work, we performed angle-dependence of magnetization and electron spin resonance (ESR) investigations on the CSL host Yb(Ni1−xCux)3Al9 with x = 0.06 (YNCA). The angle-dependent magnetization reveals a peculiar variable magnetic anisotropy. The maximum magnetization axis is parallel to the ab-plane below the field of ∼35.7 kOe while shifts to the c-axis at higher fields. The microwave responses of the CSL helicoid and ferromagnetic resonance (FMR) of the forced ferromagnetic state (FFM) are observed and appear as two resonance lines on ESR spectra with the highest intensities in the ab-plane. When the external field is rotated from H ⊥ c to H / / c , the resonance field H r 1 corresponding to the CSL helicoid decreases while H r 2 correlated with the FMR increases. Furthermore, the temperature-dependent ESR shows that the CSL persists until 15 K much higher than TC (6.4 K), which suggests a precursor phenomenon. The microwave response in YNCA provides a powerful tool for modulating and researching the CSL. [ABSTRACT FROM AUTHOR]

Co3Sn2S2, a quasi-two-dimensional system with a kagome lattice, has been found to be a magnetic Weyl semimetal recently. In this work, the anisotropies of magnetization and transport properties of Co3Sn2S2 were investigated. The high field measurements reveal a giant magnetocrystalline anisotropy with an out-of-plane saturation field of 0.9 kOe and an in-plane saturation field of 230 kOe at 2 K, showing a magnetocrystalline anisotropy coefficient Ku up to 8.3 × 105 J m−3, which indicates that it is extremely difficult to align the small moment of 0.29 μB/Co on the kagome lattice from the c axis to the ab plane. The out-of-plane angular dependence of Hall conductivity further reveals strong anisotropies in the Berry curvature and ferromagnetism, and the vector directions of both are always parallel with each other. For the in-plane situation, the longitudinal and transverse measurements for both I // a and I ⊥ a cases show that the transport on the kagome lattice is isotropic. These results provide the essential understanding of the magnetization and transport behaviors for the magnetic Weyl semimetal, Co3Sn2S2. [ABSTRACT FROM AUTHOR]