Reduction of switching current distribution in spin transfer magnetic random access memories

Abstract

In this paper, the switching current distribution by spin transfer torque is investigated for CoFeB∕MgO∕CoFeB magnetic tunnel junctions (MTJs). The distribution of the spin transfer switching current for a MTJ with junction size of 85×110nm2 is 16% when the duration of applied pulse current is 5ms. In the case of magnetization reversal with magnetic field induced by current with 5ms pulse duration, the distribution of the switching field is 8.3%. According to our micromagnetic simulation, it is found that the spin transfer current switching seems to exhibit a nonuniform magnetization reversal process, whereas the magnetization switching by the magnetic field exhibits a uniform magnetization reversal process. This leads to the broader distribution related to the repeatability.