Magneto-Optic Properties of Electroless Cobalt Alloy Films

The magneto-optic properties of electroless Co-Ni-W-Re-P plating films were studied, and on the basis of preliminary experiments, a Co-Ni-W-Re-P system containing sodium tartrate as a complex agent was chosen. The films deposited from the bath had an hcp structure with the c-axis perpendicular to the film plane. The Kerr-rotation angle (θk) and reflectivity (R) showed generally a constant value at film thickness above 0.1μm. Reflectivity varied from 60 to 80% for all specimens investigated. The Kerr-rotation angle varied over a wide range with the plating condition and it was affected considerably by Co2+/Ni2+ ion ratio in the bath. Both the (002) plane orientation and saturation magnetization (Ms) influenced the Kerr-rotation angle and it was increased by decrease in Δθ50 and increase in Ms. The maximum value of θk obtained in this study was 0.26.