Substantial reduction of write-error rate for voltage-controlled magnetoresistive random access memory by in-plane demagnetizing field and voltage-induced negative out-of-plane anisotropy field

Abstract

Voltage-controlled magnetoresistive random access memory (VC-MRAM) based on voltage-induced dynamic switching in magnetic tunnel junctions (MTJs) is a promising ultimate non-volatile memory with ultralow power consumption. However, the dynamic switching in a conventional MTJ is accompanied by a relatively high write error rate (WER), hindering the reliable operation of VC-MRAM. Here, we propose a reliable writing scheme using the in-plane demagnetizing field (IDF) and voltage-induced negative out-of-plane anisotropy field (NOAF). Numerical simulations based on macrospin model demonstrate that the voltage induced NOAF modifies the switching dynamics and increases the torque due to the IDF, thereby reducing the switching time. The IDF and voltage-induced NOAF also reduce the mean energy difference between the magnetization direction at the end of the pulse and the equilibrium direction. As a result, an appropriate combination of the IDF and voltage-induced NOAF reduces the WER by one order of magnitude compared with that of the dynamic switching in a conventional MTJ.