Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Weak ferromagnetism and magnetoelectric coupling in bismuth ferrite   We analyze the coupling between the ferroelectric and magnetic order
parameters in the magnetoelectric multiferroic BiFeO_3 using density functional
theory within the local spin density approximation and the LSDA+U method. We
show that weak ferromagnetism of the Dzyaloshinskii-Moriya type occurs in this
material, and we analyze the coupling between the resulting magnetization and
the structural distortions. We explore the possibility of
electric-field-induced magnetization reversal and show that, although it is
unlikely to be realized in BiFeO_3, it is not in general impossible. Finally we
outline the conditions that must be fulfilled to achieve switching of the
magnetization using an electric field.

20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
3
The categories of this paper are: physics
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
10
The categories of this paper are: q-bio
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
25
The categories of this paper are: patt-sol