Magnetic and high frequency properties of nanogranular CoFe-TiO2 films

A series of soft magnetic nanogranular CoFe-TiO2 films with different thicknesses were fabricated on Si substrates by co-sputtering CoFe and TiO2, and the magnetic and high frequency properties were studied in details. X-ray diffraction analysis confirmed that the films were nanocrystalline/amorphous composites. A saturation magnetization as high as 21 kGs and a ferromagnetic resonance (FMR) frequency above 3 GHz were obtained. It was found that the coercivity decreased steeply with the increase of film thickness and its minimum value was about 6 Oe. In addition, the variations of FMR peak broadness of the imaginary part and damping factor were also presented and discussed as functions of film thickness.