Crystallography and magnetic properties of CoCrTa films prepared on Cr underlayers with different substrate bias conditions

Thin CoCrTa alloy films on Cr underlayers were prepared on disk substrates by dc magnetron sputtering. The Cr thickness was varied and three bias conditions were used, viz., no bias, dc bias, and rf bias. Film morphology, crystallography, and magnetic properties were studied. Bias was observed to promote Cr 〈100〉 and Co 〈112̄0〉 preferred orientation in the films. The coercivity was observed to increase with increasing Cr thickness. The application of bias was observed to increase the coercivity and coercive squareness, and to reduce the grain size.