Polarizatoin rotation of microwaves in ferromagnets subjected to spin torque

It is well known [1] that microwaves propagating through a ferromagnetic material experience a resonance increase of polarization rotation (Faraday and Kerr effects) near the ferromagnetic resonance frequency. Here we study how this effect is modified in the presence of spin torques acting on magnetization. [1] C. L. Hogan, Rev. Mod. Phys. {\bf 25}, 253 (1953).