Field-free switching of VG-SOT-pMTJ device through the interplay of SOT, exchange bias, and VCMA effects

Field-free magnetization switching via the interplay of spin orbit torque (SOT), exchange bias field ( H E X ), and voltage controlled magnetic anisotropy (VCMA) is crucial for the development of scalable, high speed, and energy-efficient spintronic memories. This has been experimentally demonstrated by the rapid evolution of the voltage gated-spin orbit torque-magnetic random access memory (VG-SOT-MRAM) cell, in which perpendicular spin current is fed along with the in-plane H E X and VCMA assistance for cell programming. Here, we have examined the writing properties of a three terminal voltage gated-spin orbit torque-perpendicularly magnetized magnetic tunnel junction (VG-SOT-pMTJ) device structure (IrMn/CoFeB/MgO/CoFeB) in-depth through simulation. We observed that SOT critical switching current ( I _ S O T ) decreases either by increasing the VCMA voltage or FL thickness. Even SOT field-like torque can accelerate the switching process and modulate the critical switching current. As the VCMA voltage rises, I _ S O T falls by nearly 60%. In our experimental setup, VCMA/SOT optimal pulse width and amplitude for better write delay are 1 ns and 0.3 V, respectively. Furthermore, the impacts of free layer thickness, pMTJ radius, H E X , and noise are analyzed. Finally, we demonstrate the dependency of material parameters on temperature and VCMA voltage.