Magnetization reversal behavior in cobalt rare-earth thin films

Cobalt Rare-Earth (CoR,R=Pr,Sm) thin films on a Cr underlayer have shown promise as future ultra high density magnetic recording media. The activation volume or the magnetic switching volume (V*) is an important consideration for thermal stability and media noise in high density recording media and V* can also provide information about the magnetization reversal behavior in these films. The magnetic switching volume was estimated for the CoPr films with thicknesses from 28 to 639 nm with a Cr underlayer of 80 nm annealed at 500/spl deg/C. The measured switching volume ranges from 1.3 to 1.7/spl times/10/sup -18/ cm/sup 3/. We have also studied the Cr underlayer thickness and temperature effects on the switching volume for the CoSm films.