Spin resonance associated with itinerant electrons affected by the injected spin current

The effect of spin injection on the spin resonance associated with itinerant electrons in a nonmagnetic semi-conductor has been studied within the phenomenological approach. The power absorbed under the resonance conditions has been analyzed as a function of the frequency, effective $g$-factor, and magnetic field direction. It is shown that the power absorbed by the spin-polarized charge carriers under the resonance conditions can provide a tool for studying the spin injection.