Surface Relaxation and Quasiparticle Interactions in Conduction-Electron Spin Resonance

Abstract

A modified Bloch equation for the conduction-electron magnetization density is developed starting from the Landau-Silin kinetic equation, and a boundary condition describing surface relaxation is formulated. These basic results include the effects of the drift magnetization current density and predict relaxation of the magnetization density to the instantaneous local value of the applied microwave field. The conditions of validity of this and previous theories are critically discussed, and it is shown that in the collision-dominated regime, for example, the modified Bloch equation is valid only under classical-skin-effect conditions. A way of obtaining useful results for anomalous-skin-effect conditions is then outlined. Formulas for the surface impedance and for the amplitude of the microwave field transmitted through a thin metallic slab are derived.