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 D
eff
(=coherent length), the strain < ε
²
>
^1/2
, and the lattice spacing d
00.2
have 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 D
eff
for 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, D
eff
was found to increase and the saturation magnetization Ms decreased, implying that Cr segregation as well as slip bands decreased throughout the thickness.