Ferromagnetic Moment Research Articles

Noncollinear Magnetic Structures in the Chiral Antiperovskite β-Fe2SeO.

We present the magnetic properties of the chiral, polar, and possibly magnetoelectric antiperovskite β-Fe2SeO as derived from magnetization and specific-heat measurements as well as from powder neutron diffraction and Mössbauer experiments. Our macroscopic data unambiguously reveal two magnetic phase transitions at TN1 ≈ 103 K and TN2 ≈ 78 K, while Rietveld analysis of neutron powder diffraction data reveals a noncollinear antiferromagnetic structure featuring magnetic moments in the a-b plane of the trigonal structure and a ferromagnetic moment along c. The latter is allowed by symmetry between TN1 and TN2, weakly visible in the magnetization data yet unresolvable microscopically. While the intermediate phase can be expressed in the trigonal magnetic space group P31, the magnetic ground state is modulated by a propagation vector q = (1/2 1/2 0) resulting in triclinic symmetry and an even more complex low-temperature spin arrangement which is also reflected in the Mössbauer hyperfine patterns indicating additional splitting of Fe sites below TN2. The complex noncollinear spin arrangements suggest interesting magnetoelectric properties of this polar magnet.

P-Orbital Ferromagnetism Arising from Unconventional O- Ionic State in a New Semiconductor Sr2AlO4 with Insufficiently Bonded Oxygen.

Oxygen in solids usually exists in an O2- ionic state. As a result, it loses its magnetic nature of a single atom, wherein two unpaired electrons exist in its outer 2p orbitals. Here, it is shown that an unconventional stable ionic state of O- is realized in a new semiconductor material Sr2AlO4, leading to an intrinsic p-orbital ferromagnetism stable until ≈900K. Experimental and theoretical investigations have clarified that one-fourth of the oxygen atoms in Sr2AlO4 are insufficiently bonded in the crystal structure, resulting in a unique O--state and p-orbital ferromagnetism. To date, the O- state is reported to exist only in non-equilibrium conditions, and p-orbital magnetism is only suggested in impurity bands with small ferromagnetic moments. The present work provides a new route for creating ferromagnetism in semiconductors and exploring new p-orbital physics and chemistry. In addition, the material shows elastic-mechanoluminescence that may enable unprecedented mechano-photonic-spintronics.

Crystallization and phase transition boosted optical linear& nonlinear and magnetic properties in transparent xCu: BaSnO3 NCs/glass-ceramic

In this study, cubic xCu: BaSnO3 (x = 0, 1, 3, and 5 mol%) perovskite nanocrystals were synthesized using a hydrothermal method. The influence of Cu doping levels on the crystal structure, morphology, size, and properties was analyzed using X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), Raman, Ultraviolet-Visible Spectroscopy (UV–vis), Vibrating Sample Magnetometry (VSM), and X-ray Photoelectron Spectroscopy (XPS) techniques. Across the 1–5 % doping range, the cubic BaSnO3 structure was maintained with Cu2+ in CuO6 replacing Sn4+ in the B-site. XPS analysis confirmed the formation of oxygen vacancies due to charge imbalance, leading to a decrease in optical bandgap and an increase in ferromagnetic moment. When various contents of xCu: BaSnO3 were doped into borosilicate glass, significant impacts on the glass network, crystallization, and properties were observed. Nanocrystals (∼50 nm) transitioned from cubic to orthorhombic phase beyond 3 mol% doping, modifying the glass network by converting BO3 to BO4, AlO4 to AlO6, and CuO6 to CuO4. This phase change endowed the glass's strong ferromagnetic moment and absorption due to the t2 g→eg transitions of Cu2+ in CuO6, and reduced the optical bandgap from 3.16 to 2.2 eV. The glass also exhibited improved Vickers hardness (475 HV) and a high Verdet constant of 0.174 min/G·cm due to network modifications. Glass also shows a distinct red emission at 596 nm with a 160 µs lifetime and good thermal stability, while doping levels above 3 % resulted in emission quenching. The optical nonlinear absorption coefficient and nonlinear susceptibility increased with higher doping levels, reaching huge values of α3: 5.12×10−10 m/W and χ(3): 7.52×10−10 esu, indicating potential for self-focusing applications. The increased polarizability also resulted in a high dielectric constant (18) and a large P-E loop of glasses which are promising for advanced photonics devices.

Ab initio analysis of structural, electronic, magnetic, thermodynamic, and elastic properties of Half Heusler alloys ZMnAs (Z = Be, Mg) for spintronics applications

In this study, the structural, electronic, magnetic, thermodynamic, and elastic attributes of ZMnAs (Z = Be, Mg) have been investigated. These Half-Heusler alloys exhibit stability in the ferromagnetic state (FM), as demonstrated by optimization-related energy release. The half-metallicity (HM) of these compounds is examined through the band structures and density of states (DOS). In addition, the crystal field and exchange energies are reported to confirm the control of electron spin. Additionally, the double exchange process and exchange constants were premeditated. In this case, ferromagnetism (FM) is caused by the quantum exchange of electrons, as evidenced by the negative pd exchange energy and the exchange constants, rather than being a result of clustering effects. The quasi-harmonic Debye model, included within the Gibbs code, was utilized to calculate the thermodynamic properties. These two compounds are mechanically stable and show ductile nature confirmed by the value of Poisson's ratio (v), Pugh's ratio (B/G), and Cauchy pressure (CP), which demonstrates the ability to withstand substantial plastic deformation before fracturing. Based on our calculations, the half-metallic (HM) nature, thermodynamic, ferromagnetic, ductile, and high inherent magnetic moment have been evaluated. These alloys are crucial in the advancement of spintronics and renewable energy systems.

Flexible Exchange‐Biased Films with Superior Strain Stability

AbstractThe exchange bias (EB) effect plays an undisputed role in the state‐of‐art spintronic devices, both rigid and flexible. However, the poor stability of EB under mechanical strain is detrimental to the construction of reliable flexible spintronic devices, which poses a great challenge for potential wearable applications. Here, it is revealed that the strain‐induced variation of EB field can be greatly suppressed by engineering flexible IrMn/[Co/Pt]3 systems featured with perpendicular magnetic anisotropy (PMA). Particularly, in the multi‐stacks with strong PMA, poorly crystallized IrMn structure, and parallel alignment of the ferromagnetic (FM) moments with the biasing magnetic field applied during deposition, an exceptional good strain stability of EB among reported flexible systems is realized, which results from the stable perpendicular FM moments, the low strain transfer efficiency, and the eliminated strain‐driven training effect. These results provide an effective approach to develop flexible spintronic devices with superior strain stability, rendering them strong contenders in the realms of sensor and storage applications.

Spin switching in Er1-xSmxFeO3 (x = 0, 0.2) single crystals

We investigated spin-switching transitions in Er1-xSmxFeO3 (x = 0, 0.2) single crystals and variations in spin configurations with the applied field. The crystals were grown using the optical floating zone technique, and the magnetic properties were measured under field-cooled cooling (FCC) and field-cooled warming (FCW) protocols. The crystals exhibit field-dependent variation in the spin-switching temperature. In FCC, spin switching temperature increases with a magnetic field. However, in FCW, the spin-switching temperature (TSSW) rises initially with an increasing magnetic field, reaches a maximum value and later decreases when field strengths are high. We observe that spin switching depends not only on the magnitude of the externally applied magnetic field but also on the starting temperature of FCC. The magnetic and thermal history of the sample has a critical role in this phenomenon. A phase diagram (magnetic field-TSSW) constructed using the FCC and FCW data helps to illustrate various magnetic configurations. The FCC and FCW measurements in the a-direction of ErFeO3 at high fields (2T, 3T) suggest that spin switching, which involves the reversal of spins, does not occur. Instead, there is a change in the magnitude of the weak ferromagnetic moment, and rare earth spins below the compensation temperature (Tcomp).

Unconventional Magnetic and Magneto-Transport Properties in Quasi-2D Ni0.28TaSeS Single Crystal.

Van der Waals (vdW) magnetic materials have broad application prospects in next-generation spintronics. Inserting magnetic elements into nonmagnetic vdWmaterials can introduce magnetism and enhance various transport properties. Herein, the unconventional magnetic and magneto-transport phenomena is reported in Ni0.28TaSeS crystal by intercalating Ni atoms into nonmagnetic 2H-TaSeS matrix. Magnetic characterization reveals a canted magnetic structure in Ni0.28TaSeS, which results in an antiferromagnetic (AFM) order along the c-axis and a ferromagnetic (FM) moment in the ab-plane. The presence of spin-flop (SF) behavior can also be attributed to the canted magnetic structure. Temperature-dependent resistivity exhibits a metallic behavior with an abrupt decrease corresponding to the magnetic transition. Magneto-transport measurements demonstrate a positive magnetoresistance (MR) with a plateau that is different from conventional magnetic materials. The field-dependent Hall signal exhibits nonlinear field dependence when the material is in magnetically ordered state. These unconventional magneto-transport behaviors are attributed to the field-induced formation of a complex spin texture in Ni0.28TaSeS. In addition, it further investigated the angle dependence of MR and observed an unusual fourfold anisotropic magnetoresistance (AMR) effect. This work inspires future research on spintronic devices utilizing magnetic atom-intercalated quasi-2D materials.

Structural and magnetic transformations in the system YBaCo4O7+X (x = 0, 0.1, 0.2)

The modification of magnetic and elastic properties of YBaCo4O7+x (x = 0, 0.1) cobaltite series at a small controlled deviation x = 0, 0.1, 0.2 from stoichiometry has been investigated. The non-stoichiometric cobaltites with x > 0.1 are found to be separated into two structural phases with different values of x under certain synthesis and heat-treatment conditions of the YBaCo4O7+x system (x = 0, 0.1, 0.2). A non-trivial magnetic behavior is observed in stoichiometric YBaCo4O7. Magnetic moment ΔM = MFC–MZFC induced by an external magnetic field (an analog of thermo-residual magnetization) exhibits anomalies at magnetic phase transition temperatures TN1 and TN2 that coincide with Young’s modulus anomalies. Conversely, in the magnetic susceptibility curves taken in the FC and ZFC modes, phase transitions are not discerned. When x deviates from stoichiometry, the ratio between two magnetic ions Co3+/Co2+ changes, the induced moment ΔM increases, and a residual ferromagnetic moment of ∼ 10-2μB appears in the magnetization curves at low temperatures. At a slight deviation from the oxygen stoichiometry in the samples, the structural distortion disappears, and the anomalies in the elastic characteristics near the TN region rapidly diffuse and vanish. It has been found that when YBaCo4O7+x cobaltites deviate from stoichiometry, the evolution of their magnetic properties is similar to that observed at the transition from Y-based to Ca-based cobaltite. Two scenarios of the cobalt subsystem magnetic behavior with an increasing fraction of cobalt Co3+ ions have been discussed.

Stoichiometry‐Induced Ferromagnetism in Altermagnetic Candidate MnTe

AbstractThe field of spintronics has seen a surge of interest in altermagnetism due to novel predictions and many possible applications. MnTe is a leading altermagnetic candidate that is of significant interest across spintronics due to its layered antiferromagnetic structure, high Neel temperature (TN ≈ 310 K) and semiconducting properties. The results on molecular beam epitaxy (MBE) grown MnTe/InP(111) films are presented. Here, it is found that the electronic and magnetic properties are driven by the natural stoichiometry of MnTe. Electronic transport and in situ angle‐resolved photoemission spectroscopy show the films are natively metallic with the Fermi level in the valence band and the band structure is in good agreement with first‐principles calculations for altermagnetic spin‐splitting. Neutron diffraction confirms that the film is antiferromagnetic with planar anisotropy and polarized neutron reflectometry indicates weak ferromagnetism, which is linked to a slight Mn‐richness that is intrinsic to the MBE‐grown samples. When combined with the anomalous Hall effect, this work shows that the electronic response is strongly affected by the ferromagnetic moment. Altogether, this highlights potential mechanisms for controlling altermagnetic ordering for diverse spintronic applications.

Spin switching and magnetocaloric effect of high-entropy orthoferrite single crystal

The concept of high-entropy oxides/alloys was introduced into the rare-earth orthoferrite (RFeO3, R represents a rare-earth ion) system. Doping five different rare-earth ions with equal molar ratios at the R-site, a single crystal of high-entropy orthoferrite (Y0.2Sm0.2Eu0.2Gd0.2Er0.2)FeO3 (HERFO) was synthesized using optical floating zone method. At high temperatures, the weak ferromagnetic (wFM) moments induced by the distortion of the Fe sublattices align along the c axis, with a spin configuration of Γ4. As the temperature decreases, a spin reorientation transition (SRT) occurs from Γ4 to Γ2 due to the Fe3+-R3+ super-exchange interactions, with an immediate state Γ24. The wFM moments gradually rotate from the c axis to the a axis within the ac plane. In the zero-field-cooling (ZFC) mode, both the type-I and type-II spin switching (SSW) are observable along the a axis. Under low magnetic fields, the type-II SSW is magnetically controlled. The trigger temperature and variation in net moment of the type-II SSW exhibit systematic changes concerning the applied magnetic field. The rich magnetic phase transitions in HERFO make it a promising candidate for spintronic applications aimed at spin manipulation. Additionally, HERFO single crystal exhibits a large magnetocaloric effect (MCE) and magnetic entropy anisotropy, with the negative magnetic entropy change (‐ΔSm) along the c axis (14.45 J/(kg·K)) being greater than that along the a and b axes (9.57 J/(kg·K) and 10.32 J/(kg·K)). Consequently, HERFO holds great promise as a novel material for magnetic refrigeration applications aimed at achieving rotational magnetic cooling.

Microwave spin-pumping from an antiferromagnet FeBO3

Canted antiferromagnets offer great potential in fundamental research and for use in applications due to their unique properties. The presence of the Dzyaloshinskii–Moriya interaction (DMI) leads to the existence of a weak ferromagnetic moment at room temperature. We study both theoretically and experimentally microwave spin pumping by a quasi-ferromagnetic mode from a canted easy plane antiferromagnet with weak ferromagnetism FeBO3. The conversion of a microwave signal into a constant voltage is realized using the inverse spin Hall effect in an iron borate/heavy metal heterostructure. We use an additional bias magnetic field to selectively tune the resonance frequency of such a microwave detector over a wide range up to 43.5 GHz with a potential sensitivity near 2.5 µV W−1. We confirm the pure spin current nature by changing the polarity of the detected via inverse spin Hall effect voltage by switching the direction of the bias magnetic field. We believe that our results will be useful for the development of highly tunable, portable and sensitive microwave antiferromagnet-based functional devices.

Epitaxial growth and magnetic properties of Mn5(SixGe1-x)3 thin films

Structural and magnetic properties of Mn5(SixGe1-x)3 thin films were investigated. Ferromagnetic Mn5Ge3 and anti-ferromagnetic Mn5Si3 thin films have been synthesized and characterized as these compounds exhibit interesting features for the development of spintronics. Here, Mn5(SixGe1-x)3 thin films were grown on Ge(111) substrates by co-deposition using molecular beam epitaxy. Crystalline thin films can be produced with controlled Si concentrations ranging from 0 to 1. The thin films were relaxed by dislocations at the interface with the substrate. A lattice parameter variation was observed as the Si content increased, which is comparable to previous works done in bulk. Reflection high-energy electron diffraction diagrams and X-ray diffraction profiles showed that lattice parameters a and c are shrinking and that the surface roughness and crystallinity degrade as the Si amount increases. Magnetometric measurements revealed a ferromagnetic behavior for all Si concentrations. The measured average ferromagnetic moment per manganese atom decreased from 2.33 to 0.05 μB/Mn atom. No ferro to anti-ferromagnetic transition was observed contrary to the bulk Mn5(SixGe1-x)3 compound.

A first-principles study of bilayer 1T'-WTe2/CrI3: a candidate topological spin filter

The ability to manipulate electronic spin channels in 2D materials is crucial for realizing next-generation spintronics. Spin filters are spintronic components that polarize spins using external electromagnetic fields or intrinsic material properties like magnetism. Recently, topological protection from backscattering has emerged as an enticing feature that can be leveraged to enhance the robustness of 2D spin filters. In this work, we propose and then characterize one of the first 2D topological spin filters: bilayer CrI3/1T’-WTe2. To do so, we use a combination of density functional theory, maximally localized Wannier functions, and quantum transport calculations to demonstrate that a terraced bilayer satisfies the principal criteria for being a topological spin filter: namely, that it is gapless, exhibits spin-polarized charge transfer from WTe2 to CrI3 that renders the bilayer metallic, and has a topological boundary which retains the edge conductance of monolayer 1T’-WTe2. In particular, we observe that small negative ferromagnetic moments are induced on the W atoms in the bilayer, and the atomic magnetic moments on the Cr are approximately 3.2 μB/Cr compared to 2.9 μB/Cr in freestanding monolayer CrI3. Subtracting the charge and spin densities of the constituent monolayers from those of the bilayer further reveals spin-orbit coupling-enhanced spin-polarized charge transfer from WTe2 to CrI3. We demonstrate that the bilayer is topologically trivial by showing that its Chern number is zero. Lastly, we show that interfacial scattering at the boundary between the terraced materials does not remove WTe2’s edge conductance. Altogether, this evidence indicates that BL 1T’-WTe2/CrI3 is gapless, magnetic, and topologically trivial, meaning that a terraced WTe2/CrI3 bilayer heterostructure in which only a portion of a WTe2 monolayer is topped with CrI3 is a promising candidate for a 2D topological spin filter. Our results further suggest that 1D chiral edge states may be realized by stacking strongly ferromagnetic monolayers, like CrI3, atop 2D nonmagnetic Weyl semimetals like 1T’-WTe2.

Intrinsic origin of room temperature ferromagnetic ordering in (In0.97-xCoxMg0.03)2O3 thin films

The (In0.97-xCoxMg0.03)2O3 films with different Co concentration are prepared using RF magnetron sputtering. The XRD and XPS measurements show that the films are highly oriented and both Co and Mg elements present valence state of +2. The EXAFS spectra show that only substitutional Co ions exist in the film with x = 0.02. However, the films with higher Co concentration (x > 0.02) form separate phases of substitutional Co and metallic Co clusters. All the films exhibit n-type conductivity and the carrier concentration firstly decreases and then increases with Co doping. The transport mechanisms are dominated using Mott variable range hopping at low temperature and Hard bandgap hopping at high temperature. The Co dopant can effectively alter the MR characters, which undergoes a clear transition from negative MR to positive MR. All the films exhibit room temperature ferromagnetic hysteresis loop. Clear increase of ferromagnetic hysteresis loop and saturation magnetic moment are observed due to the incorporation of Co ions. The ferromagnetism is ascribed to oxygen vacancies-induced bound magnetic polarizations. The relative percentage of substitutional Co ions decrease with Co doping, which leads to the decreasing of number of bound magnetic polarons induced by oxygen vacancies, and then weaken the Ms.

Magnon thermal Hall effect via emergent SU(3) flux on the antiferromagnetic skyrmion lattice

Complexity of quantum phases of matter is often understood theoretically by using gauge structures, as is recognized by the Z2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathbb{Z}}}_{2}$$\\end{document} and U(1) gauge theory description of spin liquids in frustrated magnets. Anomalous Hall effect of conducting electrons can intrinsically arise from a U(1) gauge expressing the spatial modulation of ferromagnetic moments or from an SU(2) gauge representing the spin-orbit coupling effect. Similarly, in insulating ferro and antiferromagnets, the magnon contribution to anomalous transports is explained in terms of U(1) and SU(2) fluxes present in the ordered magnetic structure. Here, we report thermal Hall measurements of MnSc2S4 in an applied field up to 14 T, for which we consider an emergent higher rank SU(3) flux, controlling the magnon transport. The thermal Hall coefficient takes a substantial value when the material enters a three-sublattice antiferromagnetic skyrmion phase, which is in agreement with the linear spin-wave theory. In our description, magnons are dressed with SU(3) gauge field, which is a mixture of three species of U(1) gauge fields originating from the slowly varying magnetic moments on these sublattices.

Analysis of the Electronic, Magnetic, Elasto‐Mechanical, Thermoelectric, and Thermodynamic Potential of Ruthenium‐Based Full Heusler Alloys Ru2MnX (X = V and Nb)

In the search for new and novel materials for various thermo‐physical applications, we have reported the magnetic, electronic, mechanical, thermal, and thermoelectric transport properties of two full Heusler alloys (HAs), Ru2MnV and Ru2MnNb. In order to obtain a stable structure, volume optimization was carried out in the Fm‐3m (225) and F43‐m (216) space groups. The Fm‐3m space group was found to be a stable phase for both alloys. Electronic results show the metallic nature of these alloys. Ferromagnetic moments of 4.06 and 4.18 μB were obtained for Ru2MnV and Ru2MnNb, respectively. Mechanical results show a brittle nature for Ru2MnV and a ductile nature for Ru2MnNb with a high melting temperature for Ru2MnV. Thermoelectric properties such as figure of merit along with Seebeck coefficient, electrical conductivity, power factor, and thermal conductivity have also been calculated. Furthermore, the thermodynamic results of the studied materials have also been evaluated to understand the nature of various thermodynamic parameters with respect to temperature and pressure.

Significant role of thermal effects in current-induced exchange bias field switching at antiferromagnet/ferromagnet interface

The current-induced switching of in-plane exchange bias field (<i>H</i><sub>eb</sub>) has many advantages, such as switching without assistance of external magnetic field, excellent immunity to magnetic field, and robust magnetic anisotropy. However, the blocking temperature of the nanoscale antiferromagnet/ferromagnet (AFM/FM) heterostructure is relatively low and susceptible to thermal effects. Therefore, the Joule heating theoretically plays a substantial role in the switching of <i>H</i><sub>eb</sub> driven by current, but its underlying mechanism requires further investigation and verification. We prepare a series of Pt/IrMn/Py heterostructures with varying antiferromagnet IrMn thicknesses and systematically investigate the role of thermal effects in current-driven <i>H</i><sub>eb</sub> switching. These results demonstrate that under millisecond-level current pulses, Joule heating heats the device above the blocking temperature, leading to the decoupling of exchange coupling at AFM/FM interface. Simultaneously, the Oersted field and spin-orbit torque field generated by the current switch the ferromagnetic moments, and then a new <i>H</i><sub>eb</sub> will be induced along the direction of the ferromagnetic moments in the cooling process. Furthermore,in the switching process of <i>H</i><sub>eb</sub>, the anisotropic magnetoresistance curve of the AFM/FM heterostructure exhibits a temperature-dependent two-step magnetization reversal phenomenon. Theoretical analysis indicates that this phenomenon arises from the competitive relationship between exchange bias coupling at AFM/FM interface and direct exchange coupling between the ferromagnetic moments. The findings of this study elucidate the crucial role of thermal effects in the current-driven switching of <i>H</i><sub>eb</sub>, thereby contributing to the advancement of spintronic devices based on electrically controlled <i>H</i><sub>eb</sub>.

Structural characterization, electrical and magnetic properties of (In0.97-xFexMg0.03)2O3 films

Structural, electrical, and magnetic properties of (In0.97-xFexMg0.03)2O3 films with different Fe concentration are investigated. The doped Fe ions replace the In1 sites of In2O3 lattice with the mixed-valence of +2 and +3 states and form FeIn1+2VO complex based on the real-space multiple-scattering simulation. The room temperature ferromagnetic hysteresis loop of Fe/Mg co-doped In2O3 films shows ferromagnetic ordering with coercivity Hc of about 150-300 Oe. Obvious increase of ferromagnetic hysteresis loop and saturation magnetic moment with a maximum value of 8.45 emu/cm3 (x = 0.08) are observed due to the more incorporation of Fe ions. All the films exhibit n-type conductive behavior, which are mainly dominated by Mott variable range hopping with strong localization of carriers. Interestingly, the contribution of positive and negative magnetoresistance (MR) strongly correlates with Fe dopant and temperature. It can conclude that the FeIn1+2VO complex based on bound magnetic polaron model plays a key role for achieving the intrinsic ferromagnetism.

Controllable spin-triplet superconductivity states and enhanced non-dissipation spin-polarized supercurrents in YBa2Cu3O7/La0.67Sr0.33MnO3 interfaces

The interfaces between superconductors and ferromagnets serve as a nurturing environment for spin-triplet superconducting pairs, where their spins align with the ferromagnetic moments, enabling the conduction of non-dissipative spin-polarized supercurrents that hold immense potential for spintronics applications and scientific advancements. In this study, we explore the spin-triplet superconductivity and the non-dissipative spin-polarized current in the YBa2Cu3O7(YBCO)/La0.67Sr0.33MnO3(LSMO) bilayers with X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD). The induced Cu moment at the interfaces exhibits three distinct alignment states: antiparallel, perpendicular, and parallel to the net moment of the LSMO ferromagnetic layer. Remarkably, the in-plane superconducting critical current experiences a sudden enhancement and displays a slower decaying trend to the applied magnetic field when the Cu-moment undergoes a transition from the antiparallel to the perpendicular state with respect to the LSMO magnetization. These findings shed light on the manipulation of induced Cu moments at interfaces, providing valuable insights for controlling spin-triplet states and enhancing non-dissipative spin-polarized supercurrents.

Inverse exchange bias and training effect in Gd2Co0.5Mn1.5O6 with negative magnetization

The present experiments indicate that the phenomena of inverse exchange bias and negative magnetization are observed simultaneously in Gd2Co0.5Mn1.5O6 below the ferrimagnetic compensation point Tcomp. The training effect confirms the intrinsic nature of the inverse exchange bias and reveals that the frozen spins relax more slowly than the rotatable spins according to the fitting of exchange bias field (HEB) vs cycle loops (n) curve. The amplitude of HEB varies inversely with the cooling field Hcool and the inverse exchange bias is found to remain up to 50 kOe. The observed exchange bias is argued to be due to the fact that the inverse ferromagnetic moments below Tcomp can be flipped by adjusting the amplitude or direction of the magnetic field during the M(H) hysteresis loop measurement. The manipulability of the negative magnetization state is demonstrated by the remanent magnetization and magnetic switching measurements.