Dissipation through spin Coulomb drag in electronic spin dynamics

Spin Coulomb drag (SCD) constitutes an intrinsic source of dissipation for spin currents in metals and semiconductors. We discuss the power loss due to SCD in potential spintronics devices and analyze in detail the associated damping of collective spin-density excitations. It is found that SCD contributes substantially to the linewidth of intersubband spin plasmons in parabolic quantum wells, which suggests the possibility of a purely optical quantitative measurement of the SCD effect by means of inelastic light scattering.