Microwave ferromagnetic properties of as-deposited Co₂FeSi Heusler alloy films prepared by oblique sputtering

The Co₂FeSi films are deposited on Si (100) substrates by an oblique sputtering method at ambient temperature. It is revealed that the microwave ferromagnetic properties of Co₂FeSi films are sensitive to sample position and sputtering power. It is exciting that the as-deposited films without any magnetic annealing exhibit high in-plane uniaxial anisotropy fields in a range of 200 Oe-330 Oe (1 Oe=79.5775 A·m^-1), and low coercivities in a range of 5 Oe-28 Oe. As a result, high self-biased ferromagnetic resonance frequency up to 4.75 GHz is achieved in as-deposited oblique sputtered films. These results indicate that Co₂FeSi Heusler alloy films are promising in practical applications of RF/microwave devices.