All-Optical Switching of Magnetic Tunnel Junctions with Single Subpicosecond Laser Pulses

Abstract

Injecting charge or spin current can switch the magnetization in a spintronic device without an applied magnetic field, at a speed limited by spin precession. Optical switching can beat this limit, but has been achieved only in single magnetic layers, not full devices. The authors demonstrate switching in magnetic tunnel junctions (MTJs), the building blocks of spintronic technology, with 0.4-ps infrared laser pulses. Their junctions use Gd-Fe-Co alloy, which after being heated by a pulse spontaneously relaxes to the opposite magnetic state---at 100 times the record speed for MTJ switching.