Department of Physics, University of Tokyo, Tokyo 113-0033, Japan.
J Phys Condens Matter. 2011 May 4;23(17):176001. doi: 10.1088/0953-8984/23/17/176001. Epub 2011 Apr 12.
We have studied magnetism in Ti(1-x)Co(x)O(2-δ) thin films with various x and δ 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 µ(B)/Co at the surface, while in the bulk it was 0.82-2.25 µ(B)/Co, which is in the same range as the saturation magnetization of 1.0-1.5 µ(B)/Co. These results suggest an intrinsic origin of the ferromagnetism. The smaller moment of the Co atom at the surface is an indication of a magnetically dead layer of a few nanometers thick at the surface of the thin films.
我们通过软 X 射线磁圆二色性（XMCD）测量研究了不同 x 和 δ 的 Ti(1-x)Co(x)O(2-δ)薄膜中的磁性。XMCD 估计的表面铁磁矩为 0.15-0.24 µ(B)/Co，而在体相中为 0.82-2.25 µ(B)/Co，与 1.0-1.5 µ(B)/Co 的饱和磁化强度相同。这些结果表明了铁磁性的内在起源。表面 Co 原子的较小磁矩表明薄膜表面有几纳米厚的磁死层。
