We have studied magnetism in anatase Ti 1-xCo xO 2-δ (x = 0.05) thin films with various electron carrier densities, by soft x-ray magnetic circular dichroism (XMCD) measurements at the Co L 2,3 absorption edges. For electrically conducting samples, the magnetic moment estimated by XMCD was < 0.3 μ B/Co using the surface-sensitive total electron yield mode, while it was 0.3-2.4 μ B/Co using the bulk-sensitive total fluorescence yield mode. The latter value is in the same range as the saturation magnetization 0.6-2.1 μ B/Co deduced by SQUID measurement. The magnetization and the XMCD intensity increased with carrier density, consistent with the carrier-induced origin of the ferromagnetism.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)