Investigation on the Effect of Femtosecond Laser Induced Spin Transfer Torque of GdFeCo Alloy

Abstract

All-optical magnetic switching (AOS) provides a novel approach to improve writing ability and energy efficiency compared to those utilized in the mainstream magnetic data storage products. Rare earth-transition metals (RE-TM) exhibit extremely fast magnetization switching induced by one single incident linearly polarized laser pulse; however, the mechanism is still ambiguous. Here, we show by atomistic spin simulation that the laser induced spin transfer torque dominates the magnetization reversal of Fe sublattice in Gd25Fe75 alloy, and that the switching speed of Gd25Fe75 alloy is relevant to the amount of spin current. This implies that a possible helicity independent mechanism underlies the RE-TM alloy AOS process. We also find that the greater the spin current density the faster the magnetization switching, and the time magnetization reversal of Gd and Fe takes is also affected by the spin current density.

Keywords

• GdFeCo
• alloy
• atomistic spin simulation
• spin transfer torque