TEXTURE FORMATION AND MAGNETIC-PROPERTIES OF RF-SPUTTERED COCRTA-CR LONGITUDINAL THIN-FILMS

A series of CoCrTa films of different thickness were RF sputtered on 1000 A thick Cr underlayers. The in-plane coercivity has a maximum of 1670 Oe for 200 A thick CoCrTa films and then decreases to 740 Oe for 9000 A thick films. The in-plane squareness also decreases monotonically from 0.80 to 0.25 when the thickness of CoCrTa films increases from 100 A to 9000 A. By using transmission electron diffraction, we have found that CoCrTa films thinner than 400 A have a distribution of c-axes lying mostly in the film plane or tilted by an angle of about 28° with respect to the film plane. 9000 A thick CoCrTa films are dominated by perpendicularly oriented c-axes. The crystallographic texture change during the growth process of CoCrTa films could be responsible for the observed thickness dependence of the in-plane coercivity and squareness. TEM micrographs of these films show no physical voids in the grain boundaries. © 1990 IEEE