Nanosecond magnetization dynamics during spin Hall switching of in-plane magnetic tunnel junctions

摘要

We present a study of the magnetic dynamics associated with nanosecond scalemagnetic switching driven by the spin Hall effect in 3-terminal nanoscalemagnetic tunnel junctions (3T-MTJs) with in-plane magnetization. Utilizing fastpulse measurements in a variety of material stacks and detailed micromagneticsimulations, we demonstrate that this unexpectedly fast and reliable magneticreversal is facilitated by the self-generated Oersted field, and theshort-pulse energy efficiency can be substantially enhanced by micromagneticcurvature in the magnetic free layer. The sign of the Oersted field isessential for this enhancement --- in simulations in which we artificiallyimpose a field-like torque with a sign opposite to the effect of the Oerstedfield, the result is a much slower and stochastic switching process that isreminiscent of the so-called incubation delay in conventional 2-terminalspin-torque-switched MTJs.