Effect of crystal texture on the magnetic properties of thin HCP Co-Ni films

In order to study the effect of crystal texture on the coercivity and squareness ratio of ferromagnetic thin films, Co-20 wt. % Ni films of various thicknesses (500Å m) were sputter deposited on glass, single and polycrystalline substrates using a R.F. diode. The crystal texture and preferred orientation of sputtered Co-Ni films were determined by x-ray diffraction technique. The chemical composition and distribution of non-metallic elements of sputtered films were studied by energy dispersive analysis of x-ray and scanning Auger microprobe respectively. Scanning and transmission electron microscopes were used to study the structure and morphology of the films. The sputtered Co-Ni films were found to have a simultaneous presence of [0002] and [ ] orientations with a stable HCP structure. The change of preferred orientation of Co-Ni films with thickness (500Å to 1μm) resulted in dramatic changes in coercivity, squareness ratio and the shape of the M-H hysteresis loops of the films. It appeared that the magnetic behavior of these films was predominantly controlled by the texture of the films and was less sensitive towards the thickness.