Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ferromagnetism of cobalt-doped anatase TiO$_2$ studied by bulk- and
  surface-sensitive soft x-ray magnetic circular dichroism   We have studied magnetism in anatase Ti$_{1-x}$Co$_x$O$_{2-\delta}$ ({\it 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 $\mu_B$/Co using the surface-sensitive total electron yield
(TEY) mode, while it was 0.3-2.4 $\mu_B$/Co using the bulk-sensitive total
fluorescence yield (TFY) mode. The latter value is in the same range as the
saturation magnetization 0.6-2.1 $\mu_B$/Co deduced by SQUID measurement. The
magnetization and the XMCD intensity increased with carrier density, consistent
with the carrier-induced origin of the ferromagnetism.

10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
1
The categories of this paper are: cs
19
The categories of this paper are: eess
24
The categories of this paper are: dg-ga
22
The categories of this paper are: chao-dyn
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
32
The categories of this paper are: atom-ph
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
23
The categories of this paper are: solv-int
35
The categories of this paper are: mtrl-th