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arXiv · 1407.6240

Modulating spin transfer torque switching dynamics with two orthogonal spin-polarizers by varying the cell aspect ratio

B. Lacoste·M. Marins de Castro·T. Devolder·R. C. Sousa·L. D. Buda-Prejbeanu·S. Auffret·U. Ebels·C. Ducruet·I. L. Prejbeanu·L. Vila·B. Rodmacq·B. Dieny
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Abstract

We study in-plane magnetic tunnel junctions with additional perpendicular polarizer for subnanosecond-current-induced switching memories. The spin-transfer-torque switching dynamics was studied as a function of the cell aspect ratio both experimentally and by numerical simulations using the macrospin model. We show that the anisotropy field plays a significant role in the dynamics, along with the relative amplitude of the two spin-torque contributions. This was confirmed by micromagnetic simulations. Real-time measurements of the reversal were performed with samples of low and high aspect ratio. For low aspect ratios, a precessional motion of the magnetization was observed and the effect of temperature on the precession coherence was studied. For high aspect ratios, we observed magnetization reversals in less than 1 ns for high enough current densities, the final state being controlled by the current direction in the magnetic tunnel junction cell.

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B. Lacoste, M. Marins de Castro, T. Devolder, R. C. Sousa, L. D. Buda-Prejbeanu, S. Auffret, U. Ebels, C. Ducruet, I. L. Prejbeanu, L. Vila, B. Rodmacq, B. Dieny. 2014-07-23. Modulating spin transfer torque switching dynamics with two orthogonal spin-polarizers by varying the cell aspect ratio. https://doi.org/10.1103/physrevb.90.224404

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