Ultrafast magnetic switching of GdFeCo with electronic heat currents

Abstract

We report the magnetic response of Pt/Au/GdFeCo trilayers to optical irradiation of the Pt surface. For trilayers with Au thickness greater than 50 nm, the great majority of energy is absorbed by the Pt layer, creating an initial temperature differential of thousands of kelvin between the Pt/Au layers and the GdFeCo layer. The resulting electronic heat current across the metal multilayer lasts for several picoseconds with energy flux in excess of $2\phantom{\rule{0.16em}{0ex}}\mathrm{TW}\phantom{\rule{0.16em}{0ex}}{\mathrm{m}}^{\ensuremath{-}2}$ and provides sufficient heating to the GdFeCo electrons to induce deterministic reversal of the magnetic moment.