Abstract
Latent, compositional microstructures within sputtered Co-Cr film grains are investigated using transmission electron microscopy on selectively and chemically etched films, with direct high-spatial-resolution X-ray microanalysis and thermomagnetic analysis. The validity of investigating the latent segregated microstructures via chemical etching is proved for film comprising grains, each of which has a Cr-rich core surrounded by a Co-rich ring. A segregation model based on the principle of phase separation, which is derived from microstructure observations, is found to be consistent with results of thermomagnetic analysis. It is deduced that segregation, resulting from compositional phase separation in an hcp structure occurs during film growth and results in formation of perpendicular, high Co-rich in-grain microstructures intrinsic for film magnetic properties.
