Thermally activated switching of perpendicular magnet by spin-orbit spin torque

• Published in: Applied physics letters Vol. 104; no. 7
• Main Authors: Lee, Ki-Seung, Lee, Seo-Won, Min, Byoung-Chul, Lee, Kyung-Jin
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 17-02-2014
• Subjects: Applied physics; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Dependence; DIFFUSION BARRIERS; FOKKER-PLANCK EQUATION; L-S COUPLING; MAGNETS; ORBITS; PULSES; Short pulses; SPIN; Switching; Thermal energy; THRESHOLD CURRENT; Threshold currents; TORQUE
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4866186

We theoretically investigate the threshold current for thermally activated switching of a perpendicular magnet by spin-orbit spin torque. Based on the Fokker-Planck equation, we obtain an analytic expression of the switching current, in agreement with numerical result. We find that thermal energy barrier exhibits a quasi-linear dependence on the current, resulting in an almost linear dependence of switching current on the log-scaled current pulse-width even below 10 ns. This is in stark contrast to standard spin torque switching, where thermal energy barrier has a quadratic dependence on the current and the switching current rapidly increases at short pulses. Our results will serve as a guideline to design and interpret switching experiments based on spin-orbit spin torque.