A5062770807- Magnetic properties of thin films
- Magnetic and transport properties of perovskites and related materials
- Multiferroics and related materials
- Advanced Memory and Neural Computing
- ZnO doping and properties
- Physics of Superconductivity and Magnetism
- Thermal Expansion and Ionic Conductivity
- Ferroelectric and Piezoelectric Materials
- Advanced Condensed Matter Physics
- Gyrotron and Vacuum Electronics Research
- Perovskite Materials and Applications
- Particle accelerators and beam dynamics
- Quantum and electron transport phenomena
- Shape Memory Alloy Transformations
- Electrical Contact Performance and Analysis
- Terahertz technology and applications
- Magneto-Optical Properties and Applications
- Surface and Thin Film Phenomena
- Acoustic Wave Resonator Technologies
- Metal and Thin Film Mechanics
- Ferroelectric and Negative Capacitance Devices
- Photocathodes and Microchannel Plates
- Particle Accelerators and Free-Electron Lasers
Tsinghua University
2012-2023
Tokyo Institute of Technology
2021
Out-of-plane spin polarization σ
Abstract Magnetotransport is at the center of spintronics. Mn 3 Sn single crystals, an antiferromagnet that has a noncollinear 120° spin order, exhibit large anomalous Hall effect (AHE) room temperature. But such behavior remained elusive in epitaxial films. Here observation AHE‐like with in‐plane magnetic field up to temperature quasi‐epitaxial thin films, prepared by magnetron sputtering, reported. The growth both (1120)‐ and (0001)‐oriented films provides unique opportunity for comparing...
Antiferromagnetic materials, which have drawn considerable attention recently, fascinating features: they are robust against perturbation, produce no stray fields, and exhibit ultrafast dynamics. Discerning how to efficiently manipulate the magnetic state of an antiferromagnet is key development antiferromagnetic spintronics. In this review, we introduce four main methods (magnetic, strain, electrical, optical) mediate states elaborate on intrinsic origins different materials. Magnetic...
Efficient electrical switching of antiferromagnets (AFMs) is key to their use in high-density, ultrafast, nonvolatile spintronic memory. Mn${}_{2}$Au, an AFM with opposite spin sublattices, a unique metallic material, that fieldlike torque can switch its moments. However, induced by antidamping remains be verified AFMs. Here the authors demonstrate current-induced moment both (103)-oriented Mn${}_{2}$Au single layer and Mn${}_{2}$Au/Pt heterojunction respectively. The simultaneous...
Interconversion of charge and spin currents via Hall effect is one the key physical phenomena in spintronics. However, polarizations are orthogonal to both flows due restricted symmetry conditions. Here, we use noncollinear antiferromagnet ${\mathrm{Mn}}_{3}\mathrm{Pt}$, which has different magnetic mirror planes orientations, investigate dependent atypical spin-orbit torques. We observed weak generation out plane polarization $({\ensuremath{\sigma}}_{z})$...
We observe terahertz (THz) emission in Mn3Sn, Mn3Sn/Pt, and Mn3Sn/Co films excited by a femtosecond laser pulse. In the Mn3Sn film Mn3Sn/Pt heterostructures, THz originates from both magnetic-dipole superdiffusive transient spin current with different proportions. Our results unambiguously demonstrate that can be controlled structure of Mn3Sn. The (0001)-orientated produces stronger than (112¯0)-orientated counterpart because for latter one, only half kagome planes are parallel to field,...
Rich magnetic phase transition makes the antiperovskite manganese nitride Mn3AN family an ideal platform to explore anomalous Hall effect (AHE) with different configurations. Here, we report observation of AHE signals up room temperature in antiferromagnetic (AFM) (001)-oriented Mn3SnN thin films. signals, originated from Berry curvature, can be controlled by growth-induced biaxial strain, which leads modulation noncollinear AFM A relatively large strain could enhance ascribed canted...
The coercive field of ferromagnets generally increases with decreasing the sample size to hundreds nanometers mainly because (edge) defect pinning. We investigate size-dependent anomalous Hall effect (AHE) in (112¯0)-oriented noncollinear antiferromagnetic Mn3Sn films. switching (coercive field) AHE decreases abruptly when width bar nanometers, giving rise reduced from 445 30 mT for 2 μm 100 nm. This observation is contrast ferromagnetic counterpart. transition a multidomain single...
Antiferromagnets have drawn increasing attention in the last decade, for their advantages such as no stray field and ultrafast spin dynamics, giving rise to potential applications on high-density storage high frequency. We summarize recent progress control of antiferromagnetic moments by electrical methods, including both electric current field, which are important steps integration antiferromagnets toward data storage. Several methods distinguishing switching artifacts mentioned here. Then,...
The anomalous Nernst effect (ANE), the generation of a transverse electric voltage by longitudinal temperature gradient, has attracted increasing interest from researchers recently, due to its potential in thermoelectric power conversion and close relevance Berry curvature band structure. Avoiding stray field ferromagnets, ANE antiferromagnets (AFMs) advantage realizing highly efficient densely integrated thermopiles. Here, we report observation an antiperovskite noncollinear AFM,...
Out-of-plane spin polarization (${\ensuremath{\sigma}}_{z}$) has potential applications for magnetic memory with high storage density and low energy consumption. Several noncollinear antiferromagnets have been confirmed to generate ${\ensuremath{\sigma}}_{z}$ due their triangular configuration on kagome planes, including $\mathrm{Ir}{\mathrm{Mn}}_{3}$. Apart from the of (110)-oriented $\mathrm{Ir}{\mathrm{Mn}}_{3}$, we demonstrate that interface $\mathrm{Ir}{\mathrm{Mn}}_{3}$/permalloy also...
We report on investigations into the fundamental surface emission parameters, geometric field enhancement factor (β) and work function (φ), by making both Schottky-enabled photoemission measurements. The measurements were performed a copper in Tsinghua University S-band RF gun two separate experiments. Fitting our data to models for each experiment indicate that traditionally assumed high value of β(≈50-500) does not provide plausible explanation data, but incorporating low φ at some sites...
High interfacial transparency is vital to achieve efficient spin-charge conversion for ideal spintronic devices with low energy consumption. However, in traditional ferromagnetic/nonmagnetic heterojunctions, the Rashba spin-orbit coupling brings about spin memory loss (SML) and two-magnon scattering (TMS), quenching current crossing heterointerfaces. To address intrinsic deficiency of heterointerface, we design a ferromagnetic FeRh/antiferromagnetic FeRh homojunction conversion, verified by...
In conventional ferromagnet/spacer/ferromagnet sandwiches, noncollinear couplings are commonly absent because of the low coupling energy and strong magnetization. For antiferromagnets (AFM), small net moment can embody a as sizable field, however, such AFM sandwich structures have been scarcely explored. Here we demonstrate orthogonal interlayer at room temperature in an all-antiferromagnetic junction Fe2O3/Cr2O3/Fe2O3, where Néel vectors top bottom Fe2O3 layers strongly orthogonally coupled...
${\mathrm{Mn}}_{3}\mathrm{Sn}$ is an antiferromagnet with a noncollinear spin order, and the structures can be controlled by external magnetic field. When field applied, inverse triangular structure exhibits coexistence of antiferromagnetism weak ferromagnetism. Here we observe that both magnetization hysteresis loops anomalous Hall curves single-layer films present exchange bias after cooling, which are generally observed in ferromagnet/antiferromagnet bilayers. A part antiferromagnetic...
The spin mixing conductance g↑↓ of a ferromagnetic and nonmagnetic (NM) layer characterizes the transport efficiency current through interface. Exploration relationship between structural parameters such as lattice orientation NM is critical to design effective spintronics devices. Here, two types single oriented Pt Ni81Fe19 (Py) was studied experimentally, with method pumping. obtained for (100)/Py (111)/Py bilayers 8.6 ± 0.9 nm−2 10.8 1.6 nm−2, respectively, revealing fact that crystalline...
Current-driven domain-wall motion has attracted intense attention, due to its rich physics and promising application in ``racetrack'' nonvolatile memory. However, the interplay between antiferromagnetic/ferromagnetic (AFM/FM) phase boundaries current remained elusive. To investigate, authors use pulses of induce formation anisotropic FM domains an AFM matrix. The can be reversibly oriented by applied (writing) current, giving rise orthogonal alignment which could pave way for multistage...
We report on dark current and Schottky-enabled photoemission from a copper photocathode surface. Field-emitted is major gradient-limiting factor in RF cavities. Field emission generally attributed to geometrical projections the bulk surface whose field enhancement (β) emitting area (Ae) can be extracted Fowler-Nordheim (FN) plot. Measurements were made at Tsinghua S-band gun facility two separate experiments. Using traditional FN formula for fields we discovered that alone cannot explain...
Electric field control of magnetic anisotropy in ferromagnets has been intensively pursued spintronics to achieve efficient memory and computing devices with low energy consumption. Compared ferromagnets, antiferromagnets hold huge potential high-density information storage for their ultrafast spin dynamics vanishingly small stray field. However, the switching via electric remains elusive. Here we use ferroelastic strain from piezoelectric materials switch uniaxial N\'eel order reversibly...
Magnetotransport is at the center of spintronics. Mn3Sn, an antiferromagnet that has a noncollinear 120° spin order, exhibits large anomalous Hall effect (AHE) room temperature. But such behavior been remained elusive in Mn3Sn films. Here we report observation robust AHE up to temperature quasi-epitaxial thin films, prepared by magnetron sputtering. The growth both (11-20)- and (0001)-oriented films provides unique opportunity for comparing three different measurement configurations. When...
Anomalous Nernst effect (ANE), the generation of a transverse electric voltage by longitudinal temperature gradient, has attracted increasing interests researchers recently, due to its potential in thermoelectric power conversion and close relevance Berry curvature band structure. Avoiding stray field ferromagnets, ANE antiferromagnets (AFM) advantage realizing highly efficient densely integrated thermopiles. Here, we report observation an antiperovskite noncollinear AFM Mn3SnN...