Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Light-induced size changes in BiFeO3 crystals   Multifunctional oxides are promising materials because of their fundamental
physical properties as well as their potential in applications1. Among these
materials, multiferroics exhibiting ferroelectricity and magnetism are good
candidates for spin electronic applications using the magnetoelectric effect,
which couples magnetism and ferroelecticity. Furthermore, because
ferroelectrics are insulators with a reasonable bandgap, photons can
efficiently interact with electrons leading to photoconduction or photovoltaic
effects. However, until now, coupling of light with mechanical degrees of
freedom has been elusive, although ferroelasticity is a well-known property of
these materials. Here, we report on the observation, for the first time, of a
substantial visiblelight- induced change in the dimensions of BiFeO3 crystals
at room temperature. The relative light-induced photostrictive effect is of the
order of 10e-5 with response times below 0.1s. It depends on the polarization
of incident light as well as applied magnetic fields. This opens the
perspective of combining mechanical, magnetic, electric and optical
functionalities in future generations of remote switchable devices.

21
The categories of this paper are: adap-org
2
The categories of this paper are: math
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
31
The categories of this paper are: ao-sci
14
The categories of this paper are: math-ph
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
11
The categories of this paper are: hep-lat