Evaluation of intermediate states during switching in MgO-based magnetic tunnel junctions

Abstract This study investigates the switching characteristics of magnetic tunnel junctions (MTJs) used in spin-transfer-torque magnetoresistive random-access memory. MTJs are expected to exhibit parallel (P) and antiparallel (AP) states, but some MTJs exhibit an intermediate (IM) state between the P and AP states at switching. Here we analyze in detail the size dependence and write error rates (WERs) of MTJs with IM states. The number of IM states increases with increasing MTJ size. The WER is independent of MTJ size and the number of IM state but the occurrence of the IM state itself causes a writing error.