A5100613533- Magnetic properties of thin films
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Theoretical and Computational Physics
- Magnetic Properties and Applications
- Magnetic and transport properties of perovskites and related materials
- Advanced Memory and Neural Computing
- ZnO doping and properties
- Surface and Thin Film Phenomena
- Copper Interconnects and Reliability
- Magnetic Field Sensors Techniques
- Advanced Condensed Matter Physics
- Magneto-Optical Properties and Applications
- Characterization and Applications of Magnetic Nanoparticles
- Multiferroics and related materials
- Laser-Matter Interactions and Applications
- Heusler alloys: electronic and magnetic properties
- Advanced Thermodynamics and Statistical Mechanics
- Spectroscopy and Quantum Chemical Studies
- Magnetic Properties of Alloys
- Geomagnetism and Paleomagnetism Studies
- 2D Materials and Applications
- Geophysics and Sensor Technology
- Stochastic processes and statistical mechanics
- Electrical and Bioimpedance Tomography
Minzu University of China
2025
University of Arizona
2014-2024
University of Missouri
1999-2008
Ningbo University
2008
Missouri University of Science and Technology
1999
New York University
1990-1998
University of California, San Diego
1991
The electrical-transport properties of magnetic multilayered structures are dominated by three ingredients: (1) the scattering within layers that changes from one layer to another, (2) additional resistivity due roughness interfaces between layers, and (3) depends on orientation magnetization layers. In quasiclassical approach boundary is treated differently other sources. Here we present a unified treatment all sources resistivity, determine origin giant magnetoresistance observed in Fe/Cr...
We demonstrate that magnetic properties of ultrathin Co films adjacent to Gd2O3 gate oxides can be directly manipulated by voltage. The reversibly changed from an optimally oxidized state with a strong perpendicular anisotropy metallic in-plane or nearly zero magnetization, depending on the polarity and time duration applied electric fields. Consequently, unprecedentedly large change energy up 0.73 erg/cm2 has been realized in nonvolatile manner using voltages only few volts. These results...
Self-consistent determination of the key parameters in spin-charge conversion via spin pumping–induced inverse Hall effect.
Spin pumping and related phenomena have been observed recently in heavy metals topological insulators, where the spin-orbit coupling plays an essential role. We developed a spin-pumping formalism that explicitly includes at interfaces disorder layers. across interface with attendant backflow are treated on equal footing. resolve some long-standing issues conflicting conclusions about spin-diffusion length for Pt, origin of spin-memory loss metals. In addition, we predict heretofore...
The transport properties in magnetic granular films are modeled by considering the spin-dependent impurity scattering within granules and interface roughness at boundaries of granules. magnetoresistance for these is derived using formalism developed layered structures with currents perpendicular to plane layers which applicable random systems. With this model, various features observed recent experiments can be explained optimal choice parameters maximize determined.
Due to the inhomogeneous nature of multilayered structures, measured conductivities for currents parallel and perpendicular layers are different, even if local conductivity is isotropic. The derived compared which has been calculated previously. When our formalism applied Fe/Cr superlattices, interesting features magnetoresistance found that can be verified by experiments.
It has been recently found that giant magnetoresistance can also be obtained in metallic films containing magnetic particles. Based on spin-dependent scattering, we propose a model allows us to explain various features of the and predict new features. The is further extended include temperature dependence magnetoresistance.
We propose an extension of the Landau-Lifshitz-Gilbert (LLG) equation by explicitly including role conduction electrons in magnetization dynamics conducting ferromagnets. The temporal and spatial dependent order parameter m(r,t) generates both electrical spin currents that provide dissipation energy angular momentum processing magnet. resulting LLG contains highly dependence damping term thus micromagnetic simulations based on standard should be reexamined for involving narrow domain walls...
The exchange interaction between the conduction electrons and magnetic moments at interface leads to mutual conversion electron spin current magnon current. We introduce a concept of convertance which quantitatively measures induced by accumulation created interface. predict phenomena on charge drag across insulator spacer for several layered structures.
Pure spin current, a flow of angular momentum without any companying net charge, is generated in two common ways. One makes use the Hall effect normal metals (NM) with strong spin-orbit coupling, such as Pt or Ta. The other utilizes collective motion magnetic moments waves quasi-particle excitations called magnons. A popular material for latter yttrium iron garnet, insulator (MI). Here we demonstrate NM/MI/NM trilayers that these types currents are interconvertible across interfaces,...
Abstract Spintronics exploit spin‐orbit coupling (SOC) to generate spin currents, torques, and, in the absence of inversion symmetry, Rashba and Dzyaloshinskii–Moriya interactions. The widely used magnetic materials, based on 3d metals such as Fe Co, possess a small SOC. To circumvent this shortcoming, common practice has been utilize large SOC nonmagnetic layers 5d heavy (HMs), Pt, currents turn, exert torques layers. Here, new class material architectures is introduced, excluding HMs, for...
We have examined electron screening at the surface of a ferromagnetic metal. In an applied electric field, develops induced charge and magnetization. This can be described in terms novel spin-dependent field. A set integrodifferential equations for potentials is derived solved some limiting cases. The significant implication relevant to spin-polarized transport field emission magnetic tunnel junctions discussed.
It is known that the transfer of spin angular momenta between current carriers and local moments occurs near interface magnetic layers when their are noncollinear. However, to determine magnitude transfer, one should calculate transport properties far beyond regions. Based on spin-diffusion equation, we present a self-consistent approach evaluate torque for number layered structures. One salient features longitudinal transverse components accumulations intertwined from layer next, due...
In this Letter we construct a spinor transport theory and derive the equations of motion for distribution functions currents in noncollinear magnetic multilayers. We find length scale which characterizes transverse spin current is order 3 nm ferromagnetic $3d$ transition metal such as Co; alters one's prediction torque generated free layers less than nm. limit large exchange splitting reproduce results previously found across multilayers inasmuch there are no themselves limit.
In a bilayer consisting of an insulator (I) and ferromagnetic metal (FM), interfacial spin orbit scattering leads to mixing the two conducting channels FM, which results in unconventional anisotropic magnetoresistance (AMR). We theoretically investigate magnetotransport such structures by solving spinor Boltzmann transport equation with generalized Fuchs-Sondheimer boundary condition that takes into account effect at interface. find new AMR exhibits peculiar angular dependence can serve as...
Abstract Magnetic interlayer coupling is one of the central phenomena in spintronics. It has been predicted that sign can be manipulated by electric fields, instead currents, thereby offering a promising low energy magnetization switching mechanism. Here we present experimental demonstration voltage-controlled new perpendicular magnetic tunnel junction system with GdO x barrier, where large anisotropy and sizable tunnelling magnetoresistance have achieved at room temperature. Owing to...
An analytic solution to the energy barriers of two interacting single domain particles is presented. Identical volumes and uniaxial anisotropies are assumed with easy axes parallel an external magnetic field. The locations heights system analytically determined when line joining either or perpendicular lowest saddle points surface correspond reversal modes under thermal agitation. When dipole coupling not strong, mode switching asymmetric fanning coherent rotation, depending upon bond angle,...
Active manipulation of cells, such as trapping, focusing, and isolation, is essential for various bioanalytical applications. Herein, we report a hybrid electrokinetic technique manipulating mammalian cells in physiological fluids. This applies combination negative dielectrophoretic force hydrodynamic drag induced by electrohydrodynamics, which effective conductive biological With three-electrode configuration, the stable equilibrium positions can be adjusted separation focusing Cancer white...
We present a model for determining the Rashba spin-orbit coupling (RSOC) at magnetic surfaces or interfaces by explicitly taking into account interaction between inversion-symmetry-broken potential and spin-dependent electric dipoles of Bloch states. show that RSOC alone can generate perpendicular surface anisotropy comparable to observed values in transition metals. When an external field is applied across interface, induced screening modifies thus controls direction magnetization. Our...
Field-like spin orbit torque in FeMn/Pt bilayers with ultra-thin polycrystalline FeMn has been characterized through planar Hall effect measurements. A large effective field is obtained for the thickness range of 2 to 5 nm. The experimental observations can be reasonably accounted by using a macro-spin model under assumption that layer composed two sublattices unequal magnetizations. corroborates origin considering much smaller uncompensated net moments as compared NiFe. absorption current...
The temperature dependence of the magnetoresistivity is found to be much larger in Fe/Cr superlattices with rough interfaces (high magnetoresistance) than those sharp ones (small magnetoresistance). We discuss mechanisms which produce this and point out that symmetry conditions restrict putative superlattices. show enhanced magnetoresistance can explained by existence local spin excitations at roughened interfaces.
The anomalous Hall effect, observed in conducting ferromagnets with broken time-reversal symmetry, offers the possibility to couple spin and orbital degrees of freedom electrons ferromagnets. In addition charge, effect also leads accumulation at surfaces perpendicular both current magnetization direction. Here we experimentally demonstrate that accumulation, subsequent backflow, spin-charge conversion can give rise a different type related magnetoresistance, dubbed here as which has same...
Abstract Detection and manipulation of spin current lie in the core spintronics. Here we report an active control a net Hall angle, θ SHE (net), Pt at interface with ferroelectric material PZT (PbZr 0.2 Ti 0.8 O 3 ), using its polarization. The angle ultra-thin layer is measured inverse effect pulsed tunneling from ferromagnetic La 0.67 Sr 0.33 MnO electrode. polarization on (net) enhanced when thickness reduced. When thinner than 6 nm, switching even changes sign (net). This attributed to...
Anisotropic magnetoresistance (AMR), whose physical origin is attributed to the combination of spin dependent scattering and orbital coupling (SOC), usually displays simple angular dependence for polycrystalline ferromagnetic metals. By including generic Hall (SH) terms in Ohm's law, we explicitly show that various magneto-transport phenomena such as anomalous (AH), SH, planar (PH) AMR could be quantitatively related bulk We also discuss how affected by presence interfacial SOC magnetic...