Bulk and Surface Magnetization of Co atoms in Rutile   Ti_[1-x]Co_xO_[2-delta] Thin Films Revealed by X-Ray Magnetic Circular   Dichroism
  We have studied magnetism in Ti_[1-x]Co_xO_[2-\delta] thin films with various x and \delta by soft x-ray magnetic circular dichroism (XMCD) measurements at the Co L_[2,3] absorption edges. The estimated ferromagnetic moment by XMCD was 0.15-0.24 \mu\beta/Co in the surface, while in the bulk it was 0.82-2.25 \mu\beta/Co, which is in the same range as the saturation magnetization of 1.0-1.5 \mu\beta/Co. Theseresults suggest that the intrinsic origin of the erromagnetism. The smaller moment of Co atom at surface is an indication of a magnetically dead layer of a few nm thick at the surface of the thin films. 
V. R. Singh, Y. Sakamoto, T. Kataoka, M. Kobayashi, Y. Yamazaki, A.   Fujimori, F.-H. Chang, D.-J. Huang, H.-J. Lin, C. T. C...
cond-mat.mtrl-sci