Ultrafast voltage-induced switching enabled by coupling dynamics in perpendicular magnetic tunnel junction

Ultrafast magnetization switching is essential for spintronic applications, yet the switching speed of current-driven approaches such as spin-transfer torque and spin–orbit torque is fundamentally limited by magnetic damping. Here, we demonstrate voltage-driven switching in perpendicular magnetic tunnel junctions with an exchange-coupled free layer, combining voltage-controlled magnetic anisotropy and voltage-controlled exchange coupling. We achieve unidirectional reversal with a 50% probability within 87.5 ps, establishing the sub-100-ps capability of voltage-induced switching. Analysis of switching probability vs pulse width reveals an intrinsic size-dependent switching efficiency, which is enhanced as device dimensions decrease. This trend reflects the role of coupling dynamics as confirmed by macrospin simulations, establishing coupling dynamics as the key enabler of ultrafast voltage-driven switching.