Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Carrier induced ferromagnetism in room temperature ferromagnetic
  semiconductor rutile TiO2 doped with Co   A ferromagnetic semiconductor, rutile (Ti,Co)O2, exhibits anomalous Hall
effect at room temperature. Strong dependence of the anomalous Hall effect, as
well as the magneto-optic response, on the carrier concentration suggests
carrier induced ferromagnetism in this compound. Both ferromagnetic responses
are caused by the charge carriers at the band edge of host semiconductor,
indicating possibilities of spintronics devices operable at room temperature.

6
The categories of this paper are: astro-ph
11
The categories of this paper are: hep-lat
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
34
The categories of this paper are: chem-ph
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph
20
The categories of this paper are: acc-phys