Magnetic properties and microstructure of sputtered Co-Cr films

Microscopic structural parameters of sputter-deposited Co-Cr films, such as the effective crystallite size along the thickness direction Deff(=coherent length), the strain < ε²>^1/2, and the lattice spacing d00.2have been systematically studied by means of X-ray analysis and transmission electron microscopy (TEM) in conjunction with the magnetic properties. Cross-sectional observations by TEM revealed that a number of slip bands exist in the poorly oriented films. Slip and deformation bands interrupt the coherency along the c-axis in films, giving a spread to the orientation of the c-axis across the band boundaries. The effective crystallite size Defffor such poorly oriented films was found to be less than 200 Å, which is consistent with the period of contrast observed by TEM. When a film was annealed, Deffwas found to increase and the saturation magnetization Ms decreased, implying that Cr segregation as well as slip bands decreased throughout the thickness.