Spin transfer torque switching assisted by thermally induced anisotropy reorientation in perpendicular magnetic tunnel junctions

Abstract

A method to switch the magnetization of the free layer in magnetic tunnel junctions with perpendicular anisotropy is demonstrated. It consists in assisting the spin transfer switching of the magnetization by a thermally induced reorientation of the free layer magnetic anisotropy from out-of-plane to in-plane. The junction temperature increase is due to the Joule dissipation around the tunnel barrier produced by the same pulse of current which generates the spin transfer torque. This magnetic reorientation allows the spin transfer torque efficiency to be maximal since the spin polarization of the current is perpendicular to the magnetization of the free layer. Such a thermally assisted switching allows designing highly down-size scalable magnetoresistive random access memory cells with improved write efficiency.

Reducing the switching current with a Gilbert damping constant in nanomagnets with perpendicular anisotropy

“…26 These material parameters can also be varied by varying the thickness of the nonmagnetic layers adjacent to the magnetic layer. 23,26 Also, attempts have been made to reduce I sw by reducing M s 27 and D (/ K u / H k ) 28,29 in experiments. To discuss these phenomena when using a finite pulse current, we investigated the effects of M s and K u on I sw for t p ¼ 1 ns.…”

Optimization of Tunneling Magnetoresistance in Perpendicular Magnetic Tunnel Junctions With Co|Pd Reference Layers

“…Even when a relatively thick (1-1.5 nm) CoFeB interfacial layer was present at the MgO-[Co|Pd-multilayer] interface, the TMR was still low, about 30-40%. Other groups also reported low TMR in similar film structures [Bandiera 2011, Rahman 2011]. There are two potential explanations for this low TMR: incorrect texture and low spin polarization.…”

Peculiarities of stochastic motion in antiferromagnetic nanoparticles

“…While the deterministic dynamics of magnetisation vectors is used for information coding, the noise-induced stochastic behaviour facilitates the switching processes and thus is used to increase the speed of information processing (see, e.g. 1,2 ). Noise measurement is a powerful and informative tool for study of the spintronic effects in different systems 3,4 .…”