Sputter deposited strontium ferrite films with c -axis oriented normal to the film plane

M-type strontium ferrite films were deposited by radio-frequency (rf) sputtering on fused quartz substrates kept at ambient temperatures. The as-deposited films were amorphous. They crystallized on annealing at a temperature of 800 °C or higher. The films deposited at low rf power and low oxygen to argon ratio showed c-axis orientation normal to the film plane. The magnetic properties of these films were studied using vibrating sample magnetometer, polar Kerr rotation, and torque magnetometer. The perpendicular M-H loops for c-axis oriented films were nearly rectangular with coercivity of the order of 3 kOe.