Spin waves in the spin injected paramagnetic metals
We theoretically study the effect of exchange interaction on the non-equilibrium spin waves in disordered paramagnetic metals at low temperatures. We find the sign change crossover in the spectrum of the non-equilibrium spin waves near the ferromagnet - paramagnet phase transition. The damping of spin waves in the clean metal limit is small, however in the diffusive regime the propagation of spin waves is strongly suppressed. We propose the amplification of the electromagnetic field propagating through the non-equilibrium spin waves medium.