Correlation between microhardness and coercivity of electrodeposited cobalt platinum films

Recently, great interest has been raised on cobalt platinum alloys due to their possible application in perpendicular magnetic recording. Electrodeposited cobalt platinum alloys with hcp structure, [001] preferred orientation and Pt content of about 20 at.% were considered and their magnetic, compositional and microstructural properties were correlated. Lattice parameter c of electrodeposited CoPt alloys from glycine-citrate bath showed a sigmoidal dependence on Pt content. Moreover, a linear correlation between coercivity measured in the direction perpendicular to the substrate (H_c,perp) and microstructural properties, i.e. Vickers microhardness (HV) and Young modulus (Y), was observed. In the microhardness range 550 to 900 MPa, H _c,Perp of electrodeposited films increased from about 3000 Oe to 3500 Oe. Correspondingly, the Young modulus increased from 125 to 225 GPa.