Effects of B and C on the ordering of L1(0)-CoPt thin films

We have investigated the effects of B and C on the ordering of L1(0)-CoPt f ilms and confirmed the following quite different role between B and C in Co Pt. A small amount of B considerably decreases the temperature for ordering and is interstitially incorporated into L1(0)-CoPt along its c axis due to the large negative heat of solutions with Co and Pt. X-ray photoelectron s pectroscopy analyses have revealed that B atoms combine with Co and Pt. In contrast, C is not incorporated into the CoPt lattice due to its positive h eat of solution, resulting in no decrease in the ordering temperature. The present results reveal that CoPt films containing a small amount of B are p romising for high density recording media. (C) 2001 American Institute of P hysics.