Sputtered Co-Cr films: effect of substrate bias voltage on Cr concentration

Co-Cr films were prepared by RF diode sputtering on sputter-etched substrates. Varying the bias voltage V/sub b/ from 0-300 V, the saturation magnetization M/sub s/ decreases drastically with increasingV/sub b/. In the range of low V/sub b/ values this effect can be explained by homogenization of the Cr distribution. For V/sub b/ larger than -100 V, the further reduction of M/sub s/ is a consequence of the increasing Cr concentration in the Co-Cr film from 21 at.% (V/sub b/=-100 V) up to 27 at.% (V/sub b/-300 V).<>