Temperature dependence of spin pumping in YIG/NiOx/W multilayer

We report the temperature dependence of the spin pumping effect for Y₃Fe₅O₁₂ (YIG, 0.9 μm)/NiO (t_NiO)/W (6 nm) (t_NiO = 0 nm, 1 nm, 2 nm, and 10 nm) heterostructures. All samples exhibit a strong temperature-dependent inverse spin Hall effect (ISHE) signal I_c and sensitivity to the NiO layer thickness. We observe a dramatic decrease of I_c with inserting thin NiO layer between YIG and W layers indicating that the inserting of NiO layer significantly suppresses the spin transport from YIG to W. In contrast to the noticeable enhancement in YIG/NiO (t_NiO ≈ 1-2 nm)/Pt, the suppression of spin transport may be closely related to the specific interface-dependent spin scattering, spin memory loss, and spin conductance at the NiO/W interface. Besides, the I_c of YIG/NiO/W exhibits a maximum near the T_N of the AF NiO layer because the spins are transported dominantly by incoherent thermal magnons.     

Ultrafast Magnetization Precession in Perpendicularly Magnetized L1_0-MnAl Thin Films with Co_2 MnSi Buffer Layers

Perpendicularly magnetized L1₀-MnAl thin films with Co₂ MnSi bufer layers were prepared on GaAs(001) substrates by molecular-beam epitaxy(MBE).The samples with high crystalline quality show a maximum uniaxial perpendicular magnetic anisotropy constant of 1.4×10⁷ erg/cm³.Ultrafast spin dynamics with a magnetization precession frequency up to 200 GHz was investigated by using time-resolved magneto-optical Kerr effect(TRMOKE) measurements,from which the G...     

Site Preference of Se and Te in Bi_2Se_(3-x)Te_x Thin Films

The ternary topological insulators Bi₂Se_3-xTe_x have attracted a great deal of attention due to their exotic physical and chemical properties.While most of the studies focus on the properties of these ternary TIs,limited research was performed to investigate the dynamic atomic stack of its crystal structure.We prepared highquality Bi₂Se_3-xTe_x thin films on Ga As(111)B substrates using molecular beam epitaxy,characterized with Raman...     

Spin transport in epitaxial Fe3O4/GaAs lateral structured devices

Research in the spintronics community has been intensively stimulated by the proposal of the spin field-effect transistor (SFET), which has the potential for combining the data storage and process in a single device. Here we report the spin dependent transport on a Fe₃O₄/GaAs based lateral structured device. Parallel and antiparallel states of two Fe₃O₄ electrodes are achieved. A clear MR loop shows the perfect butterfly shape at room temperature, of which the intensity decreases with the reducing current, showing the strong bias dependence. Understanding the spin-dependent transport properties in this architecture has strong implication in further development of the spintronic devices for room-temperature SFETs.     

Large-Area Freestanding Weyl Semimetal WTe_2 Membranes

We report a universal transfer methodology for producing artificial heterostructures of large-area freestanding single-crystalline WTe₂ membranes on diverse target substrates.The transferred WTe₂ membranes exhibit a nondestructive structure with a carrier mobility comparable to that of as-grown films(～179–1055 cm²·V^?1·s^?1).Furthermore,the transferred membranes show distinct Shubnikov–de Haas quantum oscillations as well as weak localization/weak anti-localization.These results provide a new approach to the development of atom manufacturing and devices based on atomic-level,large-area topological quantum films.     

Mode Structures and Damping of Quantized Spin Waves in Ferromagnetic Nanowires

Magnonic devices based on spin waves are considered as a new generation of energy-efficient and high-speed devices for storage and processing of information. Here we experimentally demonstrate that three distinct dominated magneto-dynamic modes are excited simultaneously and coexist in a transversely magnetized ferromagnetic wire by the ferromagnetic resonance(FMR) technique. Besides the uniform FMR mode, the spin-wave well mode, the backward volume magnetostatic spin-wave mode, and the perpendi...     

具有大磁各向异性和高居里温度的二维笼目磁性材料Fe3As

最近，对二维铁磁材料的研究已成为自旋电子器件领域的热点。本文通过自旋极化密度泛函理论计算，设计出一种新型的二维材料Fe₃As,其居里温度(T_c)为300 K,可达到室温。预测的二维Fe₃As具有很强的面内Fe—Fe耦合，其大的磁各向异性能量(MAE)大约为366.7μeV,有助于材料维持长程铁磁序。这种二维Fe₃As的能带同时具有平带和狄拉克点的特征。值得注意的是，平带的位置与磁耦合的强度正相关。此外，在双轴应变的作用下，随着平带和费米面之间的距离不断减小，T_c也在逐渐升高。因此，Fe₃As单层有望成为二维室温自旋电子学器件的一种有前途的候选材料。     

Anisotropic Band Evolution of Bulk Black Phosphorus Induced by Uniaxial Tensile Strain

<正>We investigate the anisotropic band structure and its evolution under tensile strains along different crystallographic directions in bulk black phosphorus (BP) using angle-resolved photoemission spectroscopy and density functional theory. The results show that there are band crossings in the Z–L (armchair) direction,     

Field-and Current-Driven Magnetization Reversal and Dynamic Properties of CoFeB-MgO-Based Perpendicular Magnetic Tunnel Junctions

We report a perpendicular magnetic tunnel junction(p MTJ) cell with a tunnel magnetoresistance(TMR) ratio of nearly 200% at room temperature based on Co Fe B/Ta/Co Fe B as the free layer(FL) and a synthetic antiferromagnetic(SAF) multilayer [Pt/Co]/Ru/[Pt/Co]/Ta/Co Fe B as the reference layer(RL). The field-driven magnetization switching measurements show that the p MTJs exhibit an anomalous TMR hysteresis loop. The spin-polarized layer Co Fe B of SAF-RL has a lower critical switching field than...     

Experimental observation of interlayer perpendicular standing spin wave mode with low damping in skyrmion-hosting [Pt/Co/Ta]10 multilayer

An interlayer perpendicular standing spin wave mode is observed in the skyrmion-hosting [Pt/Co/Ta]₁₀ multilayer by measuring the time-resolved magneto-optical Kerr effect. The observed interlayer mode depends on the interlayer spin-pumping and spin transfer torque among the neighboring Co layers. This mode shows monotonically increasing frequency-field dependence which is similar to the ferromagnetic resonance mode, but within higher frequency range. Besides, the damping of the interlayer mode is found to be a relatively low constant value of 0.027 which is independent of the external field. This work expounds the potential application of the [heavy-metal/ferromagnetic-metal]_n multilayers to skyrmion-based magnonic devices which can provide multiple magnon modes, relatively low damping, and skyrmion states, simultaneously.