Technological advancement in microelectronic devices has led to an increasing demand for soft-magnetic materials at GHz frequency. The nanogranular film has attracted significant attention as a promising candidate owing to its fruitful properties and simple process. There have been some reports on Co-oxide matrix nanogranular films, which can be used in high-frequency magnetic devices and electromagnetic wave absorbers for down-sized microelectronic devices at GHz frequency . However, the high frequency response of permeability (μ-f) of Co-oxide matrix system is relatively lower than that of theoretical calculation, which is due to easy oxidation of Co. In this study, HfN ceramic has been employed as structural (matrix) phase, considering the good diffusion barrier and chemical stability of HfN . The relationship between the structure and magnetic properties of Co-HfN films was investigated.