Observation of the magnetization metastable state in a perpendicularly magnetized nanopillar with asymmetric potential landscape

Abstract

The effect of spin torque on magnetization is investigated in an MgO/CoFeB/W perpendicularly magnetized nanopillar with an asymmetric bistable potential landscape. While conventional pulse-current-induced magnetization switching has been implemented, a metastable switched state is observed under direct current (DC). The mean dwell time of the metastable state depends not only on the DC amplitude but also on the current direction. These results suggest that the damping spin Hall torque suppresses the magnetization fluctuation and realizes the metastable state.