We present a simple theoretical description of recently measured giant magnetoresistance effects in Fe/Cr layered structures. The resistivity is calculated by solving the Boltzmann transport equation with spin-dependent scattering at interfaces. magnitude effect depends on ratio layer thickness to mean free path and asymmetry for spin-up spin-down electrons. Good agreement experiment found both sandwich structures superlattices.

We study magnetoresistivity in ferromagnetic-nonmagnetic multilayers both theoretically and experimentally. The theoretical approach uses a Boltzmann equation with spin-dependent bulk interface scattering. show that the resistivity increases when magnetizations of ferromagnetic films rotate from parallel alignment to antiparallel one. Bulk contributions are studied numerically as function electron mean free path film thickness, we these two effects produce characteristically different...

We study the Kondo effect in a quantum dot coupled to ferromagnetic leads and analyze its properties as function of spin polarization leads. Based on scaling approach, we predict that for parallel alignment magnetizations strong-coupling limit is reached at finite value magnetic field. Using an equation motion technique, nonlinear transport through dot. For alignment, zero-bias anomaly may be split even absence external antiparallel symmetric coupling, peak only presence field, but shows...

Electron tunneling in a double junction consisting of two ferromagnetic electrodes, with small metallic grain between, is analyzed theoretically the Coulomb blockade regime. A new phenomenon, that oscillations magnetoresistance due to discrete charging effects, predicted. The corresponding oscillation period depends on energy, and disappear when both junctions have same spin asymmetry. interplay nonoscillatory voltage dependence also analyzed.

Charge transport accompanied by heat transfer through a single-level quantum dot coupled to ferromagnetic leads with noncollinear magnetic moments is studied theoretically in the linear and nonlinear regimes. Calculations performed framework of nonequilibrium Green's function formalism equation motion method reveal significant influence Coulomb blockade on thermal processes. The thermopower $S$ efficiency described figure merit $ZT$ depend configuration system. Two physically different...

The Kondo effect in quantum dots (QDs)-artificial magnetic impurities-attached to ferromagnetic leads is studied with the numerical renormalization group method. It shown that QD level spin split due presence of electrodes, leading a suppression effect. We find can be restored by compensating this splitting field. Although resulting resonance then has an unusual asymmetry reduced temperature, ground state still locally screened state, describable Fermi liquid theory and generalized Friedel...

Thermoelectric effects in a double quantum dot system coupled to external magnetic/nonmagnetic leads are investigated theoretically. The basic thermoelectric transport characteristics, like thermopower, electronic contribution heat conductance, and the corresponding figure of merit, have been calculated terms linear response theory Green function formalism Hartree-Fock approximation for Coulomb interactions. An enhancement thermal efficiency (figure merit $ZT$) due blockade has found....

Transport and thermoelectric coefficients (including also spin thermopower) of silicene nanoribbons with zigzag edges are investigated by ab initio numerical methods. Local density such reveals edge magnetism. As in graphene, one finds antiferromagnetic ferromagnetic ordering, polarization at antiparallel or parallel to that the other edge, respectively. Thermoelectric properties, especially Seebeck coefficient, significantly depend on electronic band structure enhanced when Fermi level is...

Tunnel magnetoresistance in a double-barrier junction with ferromagnetic electrodes, and quantum dot (or single atom) as the central part, is analyzed theoretically sequential-tunneling regime. The due to rotation of magnetic moments external electrodes from antiparallel parallel alignment. considerations are restricted case discrete level, Coulomb correlations spin-flip transitions included. tunneling current occupation numbers calculated for both configurations. It shown that electron at...

We develop a model of the current-induced torque due to spin transfer in layered system consisting two ferromagnetic layers separated by nonmagnetic layer. The description is based on (i) classical diffusion equations for distribution functions used theory current-perpendicular-to-plane giant magnetoresistance (CPP-GMR), (ii) relevant boundary conditions longitudinal and transverse components current situation quasi-interfacial absorption magnetic expressed as function usual parameters...

The indirect exchange interaction between magnetic impurities localized in a graphene plane is considered theoretically, with the influence of intrinsic spin-orbit taken into account. Such an gives rise to energy gap at Fermi level, which makes usual RKKY model not applicable. results show that effective described by range function decays exponentially distance moments. also shown depend on whether two moments belong same sublattice or are located different sublattices.

We study electronic transport through quantum dots weakly coupled to ferromagnetic leads with collinear magnetization directions. Tunneling contributions of first and second order in the tunnel-coupling strength are taken into account. analyze tunnel magnetoresistance (TMR) for all combinations linear nonlinear response, at or off resonance, an even odd dot-electron number. Different mechanisms spin accumulation various regimes give rise different TMR behavior.

The spin-wave spectra of dipolar and exchange coupled double-layer systems are investigated both theoretically experimentally. theoretical formalism is based on a macroscopic description using the Landau-Lifshitz equation motion Rado-Weertman Hoffmann boundary conditions. experimental were obtained for ${\mathrm{Ni}}_{0.8}$${\mathrm{Fe}}_{0.2}$/Pd/${\mathrm{Ni}}_{0.8}$${\mathrm{Fe}}_{0.2}$ ${\mathrm{Ni}}_{0.8}$${\mathrm{Fe}}_{0.2}$/Cr/Co by means Brillouin light scattering. From comparison...

Abstract Hartman effect for spin waves tunnelling through a barrier in thin magnetic film is considered theoretically. The assumed to be created by locally increased anisotropy field. considerations are focused on nanoscale system operating the exchange-dominated regime. We derive formula group delay τ gr of wave packet and show that saturates with increasing width, which signature predicted earlier photonic electronic systems. In our calculations, we consider general boundary conditions...

Abstract When a current is passed through non-magnetic metal with strong spin-orbit coupling, an orthogonal spin generated. This can be used to switch the magnetization of adjacent ferromagnetic layer or drive its into continuous precession. The interface, which not necessarily sharp, and crystallographic structure nonmagnetic both affect strength current-induced torques. Here, we investigate effects interface intermixing film microstructure on torques in perpendicularly magnetized Ta/Co 40...

A new mechanism of bilinear magnetoresistance (BMR) is proposed and studied theoretically within the minimal model describing surface electronic states in topological insulators. The BMR appears as a consequence second-order response to electric field, depends linearly on both magnetic field current (electric field). based interplay current-induced spin polarization scattering processes due inhomogeneities spin-momentum locking, that unavoidably appear result structural defects leads even if...

The Rashba spin-orbit coupling is a relativistic interaction appearing in systems lacking inversion symmetry such as surfaces or interfaces. It locks the electrons' spin and angular momentum enables efficient means to interconvert currents charge through direct inverse Edelstein effects. coefficient sets amplitude of but its quantification, using for instance angle-resolved photoemission spectroscopy, very challenging. authors demonstrate that can be reliably extracted from simple...

Surface-roughness effects in electrical conductivity of thin metallic and semiconducting films with self-affine fractal surfaces are considered the framework Born approximation. The surface roughness is described by $k$-correlation model, characterized exponent $H$ $(0<~H<~1),$ in-plane correlation length \ensuremath{\xi}, rms amplitude \ensuremath{\Delta}. In case shown to increase monotonically increasing from $H=0$ $H=1$ decreasing ratio $\ensuremath{\Delta}/\ensuremath{\xi}.$ For quantum...

General dispersion equations for exchange, magnetostatic and retarded waves in infinite semi-infinite ferromagnetic superlattices are derived by the 'transfer matrix' (T matrix) method. The elementary unit of under consideration consists N different layers. bulk expressed through diagonal elements T matrix whereas those surface a column D which describes boundary conditions. explicit form matrices is given 'pure' exchange dipolar waves.

The effect of a gate voltage ($V_g$) on the spin-splitting an electronic level in quantum dot (QD) attached to ferromagnetic leads is studied Kondo regime using generalized numerical renormalization group technique. We find that $V_g$-dependence QD strongly depends shape density states (DOS). For one class DOS shapes there nearly no $V_g$-dependence, for another, $V_g$ can be used control magnitude and sign spin-splitting, which interpreted as local exchange magnetic field. acquires new type...

Spin-dependent transport through two coupled single-level quantum dots attached to ferromagnetic leads with collinear (parallel and antiparallel) magnetizations is analyzed theoretically by the nonequilibrium Green function technique. Transport characteristics, in particular, linear nonlinear differential conductance tunnel magnetoresistance associated magnetization rotation from antiparallel parallel alignment, are calculated numerically intradot Coulomb interaction taken into account. The...

An important consequence of the discovery giant magnetoresistance in metallic magnetic multilayers is a broad interest spin dependent effects electronic transport through nanostructures.An example such systems are tunnel junctions -single-barrier planar or more complex ones.In this review we present and discuss recent theoretical results on electron ferromagnetic mesoscopic including two barriers.Such also called single-electron transistors.We start from situation when central part device...

Magnetic switching of a single molecular magnet (SMM) due to spin-polarized current flowing between ferromagnetic metallic leads (electrodes) is investigated theoretically. moments the are assumed be collinear and parallel magnetic easy axis molecule. Electrons tunneling through barrier coupled SMM via exchange interaction. The system, as well spin relaxation times SMM, calculated from Fermi golden rule. It shown that can reversed by applying certain voltage two electrodes. Moreover, may...