Enhanced resonance frequency in Co₂FeAl thin film with different thicknesses grown on flexible graphene substrate

Abstract The flexible materials exhibit more favorable properties than most rigid substrates in flexibility, weight saving, mechanical reliability, and excellent environmental toughness. Particularly, flexible graphene film with unique mechanical properties extensively explored in high frequency devices. Herein, we report the characteristics of structure and magnetic property at high frequency of Co 2 FeAl thin film with different thicknesses grown on flexible graphene substrate at room temperature. The exciting finding for columnar structure of Co 2 FeAl thin film laid the foundation of excellent high frequency property of Co 2 FeAl/flexible graphene structure. In-plane magnetic anisotropy field varying with increasing thickness of Co2FeAl thin film can be obtained by measurement of ferromagnetic resonance, which can be ascribed to enhancement of crystallinity and increase of grain size. Meanwhile, the resonance frequency which can be achieved by measurement of vector network analyzer with the microstrip method increase with increasing thickness of Co2FeAl thin film. Moreover, in our case with graphene film, the resonance magnetic field is quite stable though folded it twenty cycles, which demonstrates that good flexibility of graphene film and the stability of high frequency magnetic property of Co 2 FeAl thin film grown on flexible graphene substrate. These results are promising for the design of microwave devices and wireless communication equipment.