In order to propose a ferromagnet exhibiting highly spin-polarized transport, we theoretically analyzed the spin polarization ratio of conductivity bulk ${\mathrm{Fe}}_{4}\mathrm{N}$ with perovskite-type structure, in which N is located at body center position fcc-Fe. The defined by $P=({\ensuremath{\sigma}}_{\ensuremath{\uparrow}}\ensuremath{-}{\ensuremath{\sigma}}_{\ensuremath{\downarrow}})∕({\ensuremath{\sigma}}_{\ensuremath{\uparrow}}+{\ensuremath{\sigma}}_{\ensuremath{\downarrow}})$,...

We theoretically analyze the anisotropic magnetoresistance (AMR) effects of bcc Fe (+), fcc Co Ni Fe$_4$N (-), and a half-metallic ferromagnet (-). The sign in each ( ) represents AMR ratio observed experimentally. here use two-current model for system consisting spin-polarized conduction state localized d states with spin--orbit interaction. From model, we first derive general expression ratio. consists resistivity $\sigma$ spin ($\sigma=\uparrow$ or $\downarrow$), $\rho_{s \sigma}$,...

Anisotropic magnetoresistance (AMR) effect has been systematically investigated in various Heusler compounds Co2MnZ and Co2FeZ (Z = Al, Si, Ge, Ga) epitaxial films quantitatively summarized against the total valence electron number NV. It was found that sign of AMR ratio is negative when NV between 28.2 30.3, turns positive becomes below above indicating Fermi level (EF) overlaps with or conduction band edges half-metallic gap at ∼ respectively. We also find out magnitude gradually increases...

Negative anisotropic magnetoresistance (AMR) is observed in Fe4N film from 4.2 to 300 K. The AMR ratio rises with temperature a stepwise fashion near 50 K, and accompanied by change the magnetization hysteresis. Campbell Fert model extended investigate influence of spin-polarization conduction electrons on AMR, it found that negative not for majority spin ferromagnets. Consequently, concluded present study possibly clear evidence minority film, as predicted theoretically.

The anisotropic magnetoresistance (AMR) effect was systematically investigated in epitaxially grown Co${}_{2}$Fe${}_{x}$Mn${}_{1\ensuremath{-}x}$Si films against Fe composition $x$ and the annealing temperature. A change of sign AMR ratio from negative to positive clearly detected when increased 0.6 0.8. This reversal can reasonably be explained by dominant $s$-$d$ scattering process $s\ensuremath{\uparrow}\ensuremath{\rightarrow}d\ensuremath{\uparrow}$...

The negative anisotropic magnetoresistance (AMR) effect is observed in pseudo-single-crystal γ'-Fe4N films from 4 to 300 K. Below 50 K, the changes AMR ratio depend on crystal direction along which sensing current flows. A large stepwise change of [100] direction. anomalous cos (4θ) component appears curves below 30 first-principles calculation indicates that electron occupation 3d orbitals modified as magnetic moment with respect axes. behavior might be due partial density states...

Pseudo-single-crystal γ'-Fe4N films were fabricated by changing the degree of order (S) N sites, and their anisotropic magnetoresistance (AMR) effects along Fe4N[100] direction investigated. Negative AMR ratios observed in all specimens temperature range 5–300 K. Specific features — a marked increase magnitude below 50 K appearance cos 4θ term curve 30 clearly case high S, these decreased with decreasing S. The physical origin is proposed to be crystal field effect on AMR.

Anisotropic magnetoresistance (AMR) effects in Cox(MnyGa1-y)100-x Heusler alloy thin films epitaxially grown on a MgO single-crystal substrate have been investigated by changing their composition the ranges of x = 44.4–59.2 at. % and y 0.44–0.55. Negative AMR ratios were observed at measurement temperatures from 5 to 300 K for all films, indicating that Co2MnGa possible half-metallicity. The ratio changed sensitively depending films. In case film with 0.44, peaked around 50 %. addition,...

We derive a simple relational expression between the spin polarization ratio of resistivity, $P_\rho$, and anisotropic magnetoresistance $\Delta \rho/\rho$, that density states at Fermi energy, $P_{\rm DOS}$, \rho/\rho$ for nearly half-metallic ferromagnets. find $P_\rho$ DOS}$ increase with increasing $|\Delta \rho/\rho|$ from 0 to maximum value. In addition, we roughly estimate Co$_2$FeGa$_{0.5}$Ge$_{0.5}$ Heusler alloy by substituting its experimentally observed into respective expressions.

We derive the general expression of anisotropic magnetoresistance (AMR) ratio ferromagnets for a relative angle between magnetization direction and current direction. here use two-current model system consisting spin-polarized conduction state ( s ) localized d states with spin-orbit interaction. Using expression, we analyze AMR ratios Ni half-metallic ferromagnet. These results correspond well to respective experimental results. In addition, give an intuitive explanation about relation sign...

The anisotropic magnetoresistance (AMR) effect and the anomalous Hall (AHE) were investigated in temperature range of 5–300 K for a pseudo-single-crystal Mn4N thin film. sign AMR ratio changed from positive to negative when was lowered. Below 100 K, cos 2θ component curves significantly increased magnitude, 4θ appeared. Based on electron scattering theory, which takes into account tetragonal crystal field effect, it is suggested that dominant process film up-spin conduction electrons d...

We have investigated the temperature $(T)$ dependence of anisotropic magnetoresistance (AMR) effect ${\mathrm{Co}}_{2}{\mathrm{FeGa}}_{0.5}{\mathrm{Ge}}_{0.5}$ (CFGG) epitaxial thin films having different compositions and atomic orders to examine relation between AMR half-metallic electronic structure based on a developed theoretical model. The $T$ resistance change (\ensuremath{\Delta}\ensuremath{\rho}) normalized at 10 K is minimal in CFGG standard composition high order. In contrast,...

We theoretically study the twofold and fourfold symmetric anisotropic magnetoresistance (AMR) effects of ferromagnets. here use two-current model for a system consisting conduction state localized d states. The states are obtained from Hamiltonian with spin--orbit interaction, an exchange field, crystal field. From model, we first derive general expressions coefficient term ($C_2$) that ($C_4$) in AMR ratio. In case strong ferromagnet, dominant $C_2$ is proportional to difference partial...

Anisotropic magnetoresistance (AMR) effects in Cox(Mn0.44Ga0.56)100−x epitaxial thin films were investigated the temperature range of 5–300 K by changing current (I) direction to crystal axis and Co content (x). The AMR ratios mostly positive for I // Co2MnGa[100] negative Co2MnGa[110] showed peak values at x = 49.7 at% both directions. calculated from s–d scattering theory, including field with density states information first-principles calculations, well reproduced experimental features.

The anisotropic magnetoresistance (AMR) effect is one of the fundamental spin-dependent transport phenomena in ferromagnets and has been subject numerous experimental observations. However, origin AMR including sign change not fully clarified theoretically. In this paper, we observe a large negative ratio ${\mathrm{Fe}}_{0.75}{\mathrm{Co}}_{0.25}$ single-crystal thin films upon Ir addition elucidate its by theoretical model....

The resistive switching (RS) effect in various materials has attracted much attention due to its interesting physics and potential for applications. NiO is an important system RS been generally explained by the formation/rupture of Ni-related conducting filaments. These filaments are unique since they formed electroforming process, so it explore their magnetoresistance (MR) behavior, which can also shed light on unsolved issues such as nature evolution this behavior multifunctional devices....

The relationship between the oxidized state in a barrier and bias-voltage dependence on tunnel magnetoresistance (TMR) effect was examined Co90Fe10/SrTiO3(STO)/La0.7Sr0.3MnO3(LSMO) magnetic junctions using single crystalline LSMO electrode STO barrier. A TMR junction, whose fabricated stoichiometrically, exhibited an asymmetric with regard to bias direction. However, when had oxygen deficiency, ratio reduced symmetrically. deficiency of is probably cause interfacial electron scattering...

Abstract We theoretically study magnetization direction dependence of the anisotropic magnetoresistance (AMR) effect a strong ferromagnet. here use two‐current model which takes into account s – d scattering, where ( ) is conduction state (the localized states). The states have spin–orbit interaction, exchange field, and crystal field tetragonal symmetry. From model, we derive analytic expressions twofold fourfold symmetric terms AMR ratio. dominant component in term proportional to...

Transverse anisotropic magnetoresistance (AMR) effects, for which magnetization is rotated in an orthogonal plane to the current direction, were investigated at various temperatures, order clarify structural transformation from a cubic tetragonal symmetry pseudo-single-crystal Fe4N film, predicted usual in-plane AMR measurements by theory taking into account spin-orbit interaction and crystal field splitting of 3d bands. According phenomenological AMR, derives only symmetry, cos 2θ component...

The anomalous Hall effects (AHE) were investigated at various temperatures for the pseudo-single-crystal Fe4N films, deposited on MgO substrates with changing degree of order (S) nitrogen site. Both resistivity and longitudinal simply decrease lowering temperature all specimens. AHE films is presumed to arise from an intrinsic mechanism because relationship between resistivity. conductivity, σAH, exhibits a specific behavior low temperature. In case film S = 0.93, σAH drastically drops below...