Induced versus intrinsic magnetic moments in ultrafast magnetization dynamics

Abstract

One of the ultimate goals for future spintronic applications is to manipulate magnetic states of matter on the shortest of timescales. Here, the authors investigate the optically induced ultrafast demagnetization and remagnetization dynamics of ferromagnetic alloys based on either intrinsic or induced magnetic moments. Using pump-probe spectroscopy in combination with dynamic spin model simulations, they find that a CoFeB alloy with intrinsic magnetic moments on the Fe and Co sites reveals a distinct asymptotic amplitude limit of the remagnetization process, while in FePt the induced moments of the Pt sites stay always proportional to those of Fe.