Magnetic and microstructural properties of CoPtTi thin films

The magnetic and structural properties of rf sputtered CO1-x-yPtxTiythin films are presented. At low argon pressure (PAr= 3×10^-3Torr) samples with high coercive field and high in plane loop squareness S is obtained, Hcbeing maximum for x = 0.17. Deposition under an applied d.c. field permitted to increase Hcwhile the substitution of a small amount of Ti improves S. For higher PAr(PAr= 8×10^-3Torr), a perpendicular anisotropy field Hp is developped. These results are correlated with the structural properties. For 0.1<×<0.25, one detects predominantly a hcp structure built up of microstructurally two different areas : well defined polycrystals and textured regions, with the c-axis oriented respectively parallel and perpendicular to the film plane. The values of Hc, S and Hp are essentially related to the respective evolution of these two regions.