A comparative study of Co and Fe thin films deposited on GaAs(0 0 1) substrate

The magnetization and the coercivity of Co and Fe thin films in the thickness range 10–200 nm deposited onto GaAs(0 0 1) substrate were studied. Coercivity of Co and Fe thin films increases with increase in film thickness. Coercivity increased from 10 to 80 Oe as thickness of Co films increased from 50 to 100 nm. In the Fe/GaAs system, coercivity increased from 30 to 180 Oe as thickness of Fe films increased from 40 to 100 nm. The surface roughness measurements of Fe films indicate that enhancement of coercivity is due to surface roughness of the film. On the other hand, it was observed from the AFM study that the enhancement of coercivity was not due to surface roughness of Co film. It is speculated that the enhanced coercivity of Co/GaAs is due to a special interaction between Co film and GaAs substrate, since the enhancement of coercivity did not appear in Co films deposited on Si(0 0 1) substrate.