Annealing effect on the magneto-electric properties of SOT-MTJs from micro to nano-sized dimensions

Abstract Spin–orbit torque magnetic random-access memory exhibits great potential for next-generation memory. Annealing is an essential process for SOT magnetic tunnel junctions (SOT-MTJs) thin films. To optimize the SOT-MTJ thin films, studying the different dimensions from micro-size to nano-size is very necessary. Here, we investigate the annealing effect on magneto-electric properties of micro-scaled and nano-scaled SOT-MTJs. The tunnel magnetoresistance (TMR) and critical current density ( J c ) increase after annealing, attributing to the improved crystallization of CoFeB layers and perpendicular magnetic anisotropy (PMA), respectively. However, the TMR increment of micro-scaled SOT-MTJ is larger than that in nano-scale, due to the reduced defects of micro-scaled SOT-MTJs by annealing. Additionally, the J c of nano-scaled SOT-MTJ is decoupled from that of micro-scaled SOT-MTJ because of the improved PMA and diminished thermal effect. This work assesses the different annealing effects in micro- and nano-sized dimensions and supplies experiment foundations to optimize the performance of SOT-MTJs.