Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: HfO$_2$: a new direction for intrinsic defect driven ferromagnetism   In view of the recent experimental reports of unexpected ferromagnetism in
HfO$_{2}$ thin films, we carried out first principles investigations looking
for magnetic order possibly brought about by the presence of small
concentrations of intrinsic point defects. {\it Ab initio} electronic structure
calculations using density functional theory (DFT) show that isolated cation
vacancy sites in HfO$_{2}$ lead to the formation of high spin defect states.
Furthermore these appear to be ferromagnetically coupled with a rather short
range magnetic interaction, resulting in a ferromagnetic ground state for the
whole system. More interestingly, the occurrence of these high spin states and
ferromagnetism is in the low symmetry monoclinic phase of HfO$_{2}$. This is
radically different from other systems previously known to exhibit point defect
ferromagnetism, warranting a closer look at the phenomenon.

27
The categories of this paper are: comp-gas
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
3
The categories of this paper are: physics
1
The categories of this paper are: cs
37
The categories of this paper are: supr-con
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
26
The categories of this paper are: bayes-an
25
The categories of this paper are: patt-sol
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
9
The categories of this paper are: nlin
18
The categories of this paper are: econ