Structure and magnetic properties of co-sputtered Co-C thin films

We studied the structure and magnetic properties of co-sputtered Co1-xCx th in films using a transmission electron microscope (TEM) and a SQUID magneto meter. These properties were found to depend critically on deposition tempe rature, T-s, and composition, x. Generally, phase separation into metallic Co and graphite-like carbon phases proceeds with increasing T-s and decreas ing x. Plan view and cross-sectional TEM images of the films prepared showe d that Co grains about 10-20 nm in diameter and 30-50 nm in height are thre e-dimensionally separated by graphite-like carbon layers 1-2 nm thick. Opti mum magnetic properties with saturation magnetization of 380 emu/cc and coe rcivity of 400 Oe were obtained for a film with x = 0.5 and T-s = 350 degre es C. (C) 1999 Elsevier Science B.V. All rights reserved.