PREPARATION AND MAGNETIC-PROPERTIES OF STRONTIUM FERRITE THIN-FILMS

Strontium ferrite films were deposited by rf sputtering of a commercial strontium ferrite target onto fused quartz substrates maintained at temperatures up to 900 degrees C. Films deposited at T < 800 degrees C were amorphous, but films deposited at T > 800 degrees C had crystalline M-type strontium ferrite structures. The film composition corresponded to that of the target. Films deposited at 800 degrees C were partially oriented in the [110] direction with the c-axis in the plane. Postannealing led to an increase in the magnetization, indicating incomplete formation of ferrite in the as-deposited state. Both in-plane and perpendicular hysteresis loops are rectangular with remanence ratios of 0.8 and 0.6, respectively, showing partial orientation with the c-axis. The torque curve is consistent with the above, although there are some additional anomalous peaks.