Spin transfer torque (STT) MRAM and beyond

Spin transfer torque (STT) MRAM is a promising scalable nonvolatile memory that may have fast speed, long endurance and low power consumption. In order to realize all these advantages, we first review the key requirements for storage materials with perpendicular magnetic anisotropy (PMA). STT-switching current is too high for low-power application due to low-energy efficiency. Among different types of alternative switching methods, electric field (EF) assisted switching is the most promising candidate. We proposed Oersted field guided EF switching and EF pulse width controlled switching for ellipse cells. Our experimental results show that even with an external field of ±5 Oe, the magnetization switching can be realized through applying an electric field. Our simulation results show that for ellipse cells, the bi-state switching can be controlled by EF pulse width without any external field.