The magneto-optical Barnett effect in metals (invited)

The interaction of polarized light with a spin in the presence of dissipation and fluctuations is shown to be equivalent to a spin transfer process that can cause switching. In high energy plasmas, the spin transfer is dominated by a spin-spin exchange term while at lower energy densities it is dominated by an optical Barnett-like effect and dissipation. This latter effect is used in conjunction with optical boson modes to predict femtosecond magnetization reversal believed to be recently measured in GdCoFe thin films. Conventional approaches based on the Bloch and the Landau–Lifshitz equations are valid only for weak coupling to the environment and hence are unable to reproduce this ultrafast switching.