Time-resolved studies of the spin-transfer reversal mechanism in perpendicularly magnetized magnetic tunnel junctions

Abstract

Miniaturized magnetic tunnel junctions enable single-shot time-resolved studies of magnetization reversal driven by spin currents that can test basic physical models, particularly as recent technological advances enable the study of sub-100 nm diameter junctions. The junctions consist of two magnetic layers with uniaxial magnetic anisotropy separated by a thin insulating layer that enables electron tunneling and thus transfer of spin-angular momentum in the tunneling process. One magnetic layer is free to reverse in response to the spin current while the other is fixed. Pulsed current measurements show the stochastic nature of the reversal process on nanosecond time scales and provide evidence for nonuniform magnetization reversal processes in junctions that are larger than 50 nm in diameter.