The results of the creation of a high-temperature spin injector based on EuO: Fe composite material are discussed. Their magnetic, electrical, structural and resonance parameters are given in a wide range of temperatures and an external magnetic field. A model calculation of the electronic spectrum of the solid solution Eu–Fe–O, responsible for the manifestation of the outstanding properties of the composite, is performed. The possibility of creating semiconductor spin electronics devices capable of operating at room temperature is shown.