The high frequency magnetic properties of self assembled Fe–Co–Si–N nanogranular thin films

The effect of a variation in Si and N concentration on the microstructure, crystal structure and high-frequency magnetic properties of Fe–Co–Si–N nanogranular thin films was investigated. The films, prepared by rf magnetron sputtering, consisted of nanosized grains of FeCo as well as a Si and N rich intergranular amorphous phase. The Si concentration had a significant effect on the crystal structure of the FeCo phase. The resistivities of the Fe–Co–Si–N films were significantly enhanced by an increase in Si concentration. The resonant frequency of the Fe–Co–Si–N films could be tuned from 0.45 GHz to 2.1 GHz by controlling Si concentration. The N concentration greatly influenced magnetic properties and the variation in resonant frequency is in agreement with Kittel’s equation. Y. Liu · Z.W. Liu · C.Y. Tan · C.K. Ong Centre for Superconducting and Magnetic Materials, Department of Physics, National University of Singapore, Singapore 117542, Singapore Y. Liu · R.V. Ramanujan ( ) · Z.W. Liu School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore e-mail: [email protected] Z.W. Liu School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, P.R. China C.Y. Tan Institute of Materials Research and Engineering, 3 Research Link, Singapore 117602, Singapore X. Zhao · E. Liu School of Mechanical & Aerospace Engineering, Nanyang Technological University, Singapore 639798, Singapore