Magnetic and microstructural properties of CoPtTi thin films

The magnetic and structural properties of rf sputtered CO
1-x-y
Pt
x
Ti
y
thin films are presented. At low argon pressure (P
Ar
= 3×10
^-3
Torr) samples with high coercive field and high in plane loop squareness S is obtained, H
c
being maximum for x = 0.17. Deposition under an applied d.c. field permitted to increase H
c
while the substitution of a small amount of Ti improves S. For higher P
Ar
(P
Ar
= 8×10
^-3
Torr), 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 H
c
, S and Hp are essentially related to the respective evolution of these two regions.