Growth rate dependence of the extrinsic magnetic properties of electrodeposited CoPt films

The magnetic properties and the magnetization process of electrodeposited thick films of Co-rich CoPt alloys are studied with particular emphasis on the effects of growth rate, controlled by varying the plating current density, and of lateral confinement, analyzing patterned micro-cylinders. We find that varying the plating current density has virtually no effect on the composition of the samples, and hence on the intrinsic magnetic properties, a substantial increase of both coercivity and squareness is obtained when the current is raised. The films are fine-grained, oriented polycrystals with typical grain sizes in the range 50–150 nm, depending on the growth rate. The complex magnetization process is studied in detail by Magnetic Force Microscopy and shown to be governed by interaction domains. It is shown that further improvement of the squareness can be obtained by exploiting the lateral confinement in patterned samples.