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The tunnel magnetoresistance (TMR) of F/O/F magnetic junctions, (F's are ferromagnetic layers and O is an oxide spacer) in the presence of magnetic impurities within the barrier, is investigated. We assume that magnetic couplings exist both…

Materials Science · Physics 2009-10-31 A. Vedyayev , D. Bagrets , A. Bagrets , B. Dieny

The spin-polarized transport is investigated in a new type of magnetic tunnel junction which consists of two ferromagnetic electrodes separated by a magnetic barrier and a nonmagnetic metallic spacer. Based on the transfer matrix method and…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Ali A. Shokri , Alireza Saffarzadeh

This paper describes a numerical experiment of magnetization switching driven by spin-polarized current in high-TMR magnetic tunnel junctions (TMR>100%). Differently from other works, the current density distribution throughout the…

Other Condensed Matter · Physics 2015-05-13 D. Aurelio , L. Torres , G. Finocchio

We study the bias-dependent spin-transfer torque in magnetic tunnel junctions in the Stoner model by scattering theory. We show that the in-plane (Slonczewski type) torque vanishes and subsequently reverses its direction when the bias…

Materials Science · Physics 2009-11-13 Jiang Xiao , Gerrit E. W. Bauer , Arne Brataas

The dependence of tunneling magnetoresistance and spin-transfer torque in FeCo/MgO/FeCo tunnel junctions on the Co concentration and the bias voltage are investigated ab initio. We find that the tunneling magnetoresistance decreases with…

Mesoscale and Nanoscale Physics · Physics 2014-02-07 Christian Franz , Michael Czerner , Christian Heiliger

We derive an expression for the spin-current through a tunnel barrier in terms of many-body Green's functions. The spin current has two contributions. One can be associated with angular-momentum transfer by spin-polarized charge currents…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Matthias Braun , Jürgen König , Jan Martinek

When a spin-polarized current flows through a ferromagnet, the local magnetization receives a spin torque. Two consequences of this spin torque are studied. First, the uniformly magnetized ferromagnet becomes unstable if a sufficiently…

Materials Science · Physics 2015-06-25 Z. Li , J. He , S. Zhang

The effect of spin-disorder scattering on perpendicular transport in a magnetic monolayer is considered within the single-site Coherent Potential Approximation (CPA). The exchange interaction between a conduction electron and localized…

Disordered Systems and Neural Networks · Physics 2009-11-07 Alireza Saffarzadeh

We consider a quasi one-dimensional configuration consisting of two small pieces of ferromagnetic material separated by a metallic one and contacted by two metallic leads. A spin-polarized current is injected from one lead. Our goal is to…

Mesoscale and Nanoscale Physics · Physics 2007-06-13 J. Peguiron , M. -S. Choi , C. Bruder

Thermal spin-transfer torque describes the manipulation of the magnetization by the application of a heat flow. The effect has been calculated theoretically by Jia et al. in 2011. It is found to require large temperature gradients in the…

Tunneling Magnetoresistance between two ferrromagnets is an issue of fundamental importance in spintronics. In this work, we show that tunneling magnetoresistance can also emerge in junctions composed of ferromagnets and time-reversal…

Mesoscale and Nanoscale Physics · Physics 2016-02-09 Zhongbo Yan , Shaolong Wan

Application of Bardeen's tunneling theory to magnetic tunnel junctions having a general degree of atomic disorder reveals the close relationship between magneto-conduction and voltage-driven pseudo-torque, as well as the thickness…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 J. Slonczewski

We predict an anomalous bias dependence of the spin transfer torque parallel to interface, $T_{||}$, in magnetic tunnel junctions (MTJ), which can be selectively tuned by the exchange splitting. It may exhibit a sign reversal {\it without}…

Other Condensed Matter · Physics 2007-05-23 Ioannis Theodonis , Nicholas Kioussis , Alan Kalitsov , Mairbek Chshiev , William Butler

We study spin and charge diffusion in metallic-ferromagnet/topological-insulator junctions. The coupled diffusion equations are derived perturbatively with respect to the strength of the interlayer tunneling. We calculate spin accumulation…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 Takehito Yokoyama , Yaroslav Tserkovnyak

The thermal spin-transfer torque (TSTT) is an effect to switch the magnetic free layer in a magnetic tunnel junction by a temperature gradient only. We present ab initio calculations of the TSTT. In particular, we discuss the influence of…

Mesoscale and Nanoscale Physics · Physics 2015-06-17 Christian Heiliger , Michael Czerner

We calculate the spin-transfer torque in Fe/MgO/Fe tunnel junctions and compare the results to those for all-metallic junctions. We show that the spin-transfer torque is interfacial in the ferromagnetic layer to a greater degree than in…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Christian Heiliger , M. D. Stiles

A mesoscopic spin valve is used to determine the effective spin polarization of electrons tunneling from and into ferromagnetic transition metals at finite voltages. The tunneling spin polarization from the ferromagnet (FM) slowly decreases…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 S. O. Valenzuela , D. J. Monsma , C. M. Marcus , V. Narayanamurti , M. Tinkham

We examine the spin torque (ST) response of magnetic tunnel junctions (MTJs) with ultra-thin MgO tunnel barrier layers to investigate the relationship between the spin-transfer torque and the tunnel magnetoresistance (TMR) under finite…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 G. D. Fuchs , J. A. Katine , S. I. Kiselev , D. Mauri , K. S. Wooley , D. C. Ralph , R. A. Buhrman

Understanding the magnetization dynamics induced by spin transfer torques in perpendicularly magnetized magnetic tunnel junction nanopillars and its dependence on material parameters is critical to optimizing device performance. Here we…

Mesoscale and Nanoscale Physics · Physics 2021-04-14 Jamileh Beik Mohammadi , Andrew D. Kent

The dynamics of a single spin embedded in the tunnel junction (quantum point contact) between ferromagnets is addressed. Using the Keldysh technique, we derive a quantum Langevin equation. As a consequence of the spin-polarization in the…

Mesoscale and Nanoscale Physics · Physics 2011-11-09 J. Fransson , Jian-Xin Zhu