Voltage-controlled magnetic anisotropy: MRAM above GHz operation with ultra-low power consumption

In recent decades, the spin-transfer-torque (STT) effect has been largely investigated as a novel writing technique in MTJ-based MRAM devices, allowing to reduce the writing time down to a few nanoseconds. But to achieve operating frequencies in the GHz regime is required a large spin-polarized current through the oxide, causing degradation of the barrier and high power consumption. To reduce the power consumption without affecting the writing speed, alternative mechanisms such as voltage-controlled magnetic anisotropy started to be studied. This Ph.D. work aims to carry out a deep investigation of such a novel writing scheme. The research will focus on the exploration of new materials for the MTJ stack and on the characterization of the device, evaluating the most important parameters (as the WER, the read disturbance rate and the VCMA coefficient), with the target to increase the writing speed above the GHz regime maintaining a low energy consumption and a high write/read reliability.