Demonstration of Electron-Mediated Voltage-Controlled Exchange Coupling in Perpendicular Magnetic Tunnel Junctions

Abstract

Electron-mediated voltage control of exchange coupling (EM-VCEC) has been proposed as a mechanism for magnetization switching via modulation of spin-dependent electron reflection. However, its experimental verification has been challenging due to the coexistence of slower, voltage-induced ionic effects. Here, we fabricate magnetic tunnel junction (MTJ) devices that enable nanosecond timescale voltage application. Our results reveal rapid exchange coupling modulation on the nanosecond timescale, consistent with an electronic origin. The observed enhancement and saturation at low temperatures further rule out ionic migration, conclusively confirming the electronic nature of the mechanism. These results establish EM-VCEC as a viable mechanism for fast and energy-efficient voltage-driven magnetic switching.