Abstract
The c-axis oriented Ba-ferrite thin films without underlayer were prepared, and their magnetic properties and crystal structures were investigated. Ba-ferrite thin films were deposited on fused quartz substrates, which were kept at room temperature, using rf diode magnetron sputtering apparatus. Two kinds of Ba-ferrite target disks were used; one was FeBa ratio of 6.5 and another was that of 16. The films with a thickness of 20 nm were deposited by using the target with Fe/Ba ratio of 16, and then annealed at 800°C for 5 hrs in air. They were not crystallized, but the films deposited by using the target with Fe/Ba ratio of 6.5 and then annealed at 800°C for 5 hrs in air were crystallized. Thus using target with Fe/Ba ratio of 6.5 is found to be useful for reduction of thickness. Moreover, the c-axis of Ba-ferrite films was oriented perpendicular to the film surface that was caused by the effect of { 111 } oriented Fe3O4 formed at interface between film and substrate. It was confirmed that the {111} oriented Fe3O4 was formed because of diffusion of Ba ions to the substrate.
