The thermal stability improvement of spin-orbit-torque (SOT) devices with a thin PtMn insertion

For the 1
^st
time, we propose a novel design of spin-orbit-torque (SOT) magnetic tunnel junction (MTJ) cells in which a thin antiferromagnetic (AFM) material is inserted between the CoFeB-based free layer and SOT channel to improve device thermal stability. This insertion strengthens not only the cell thermal stability for better data retention performance but also the immunity to the external magnetic field disturbance due to coercivity (H
c
) enhancement. The SOT cells with a PtMn insertion show the shift of R-H loop by applying a write current in the SOT channel and is reversible. Since the specific write current density (J
bias
) affects the AFM exchange bias direction, the PtMn-inserted SOT cells can reduce the unilateral switching current. In this circumstance, the PtMn-inserted SOT cells can optimize the trade-off between switching current density (J
c
) and thermal stability (Δ).