Ba-Ferrite Films Prepared by Sol-Gel Pyrolysis Method

Crystallographic and magnetic properties of Ba-ferrite films prepared by a sol-gel pyrolysis method were investigated. A solution of Ba- and Fe-nitrates dissolved in ethylene glycol became a gel with an appropriate viscosity by ultrasonic stirring at 80°C. Films were spin-coated onto SiO2/Si substratesr dried and then heated in air at various temperatures. In films prepared at a composition ratio of Fe2/Ba=5, a drying temperature Td=250°C and a crystallizing temperature TC=800°C, single-phase Ba-ferrite was obtained, and the magnetization at 10 kOe field σ10kand coercivity Hcwere 47.0 emu/g and 3 ~ 4 kOe, respectively. Films prepared at Td=250°C had smooth surfaces without any cracks. In thin films of thickness 900Å, preferred orientation of the c-axis was observed.