Highly c-axis oriented, self-biased and low loss barium ferrite thin films by sol-gel method

Barium ferrite (BaM) thin films are deposited on Pt/TiO2/SiO2/Si wafers by sol-gel, and the orientation, self-biased property and millimeter wave loss were investigated. It is found that BaM has highly c-axis orientation, and the degree of texturing is as high as 0.97. Hysteresis loops reveal that saturated magnetization (4πMS) is 4.1 kG, remanent magnetization is 94% of 4πMS, and BaM offer high self-biased property. In addition, the ferromagnetic resonance (FMR) measurement indicated that this thin film yields an anisotropy field of 15.8 kOe, and a smallest FMR linewidth of 118 Oe at 50 GHz. These phenomenon mean that this BaM thin film is suitable for application in millimeter wave devices such as circulator, filter and phase shifters, etc.