Voltage Dependence of Spin Transfer Torque in Magnetic Tunnel Junctions

Abstract

Theoretical investigations of spin transfer torque in magnetic tunnel junctions using the tight-binding model in the framework of non-equilibrium Green functions formalism are presented. We show that the behavior of the spin transfer torque as a function of applied voltage can vary over a wide range depending on the band parameters of the ferromagnetic electrodes and the insulator that comprise the magnetic tunnel junction. The behavior of both the parallel and perpendicular components of the spin torque is addressed. This behavior is explained in terms of the spin and charge current dependence and on the interplay between evanescent states in the insulator and the Fermi surfaces of ferromagnetic electrodes comprising the junction. The origin of the perpendicular (field-like) component of spin transfer torque at zero bias, i.e. exchange coupling through the barrier between ferromagnetic electrodes is discussed.

5 pages,4 figures

References in corpus (6)

• Anatomy of Spin-Transfer Torque
• Measurement of the Spin-Transfer-Torque Vector in Magnetic Tunnel Junctions
• Currents, Torques, and Polarization Factors in Magnetic Tunnel Junctions
• Anomalous Bias Dependence of Spin Torque in Magnetic Tunnel Junctions
• Effect of interface bonding on spin-dependent tunneling from the oxidized Co surface
• A selfconsistent theory of current-induced switching of magnetization

Cited by in corpus (9)

• Switching Distributions for Perpendicular Spin-Torque Devices within the Macrospin Approximation
• Bias and angular dependence of spin-transfer torque in magnetic tunnel junctions
• Bias dependence of perpendicular spin torque and of free and fixed layer eigenmodes in MgO-based nanopillars
• Analytical description of ballistic spin currents and torques in magnetic tunnel junctions
• Bias dependence of tunneling magnetoresistance in magnetic tunnel junctions with asymmetric barriers
• Bidirectional switching assisted by interlayer exchange coupling in asymmetric magnetic tunnel junctions
• Twist in the bias-dependence of spin-torques in magnetic tunnel junctions
• Spin transfer exchange torque in ferromagnet/ferromagnet structures made of half metals with large exchange gaps
• Influence of image forces on the interlayer exchange interaction in magnetic tunnel junctions with ferroelectric barrier