Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Oxygen vacancies induced ferroelectricity in relaxors with ABO3
  structure   The consideration of oxygen vacancies influence on the relaxors with
perovskite structure was considered in the framework of
Landau-Ginzburg-Devonshire phenomenological theory. The theory applicability
for relaxors is based on the existence of some hidden soft phonon polar mode in
them, and its frequency could be zero at some negative temperature TC*. Main
attention was paid to PZN-PLZT relaxor described by formula
0.3Pb(Zn1/3Nb2/3)O3-0.7(Pb0.96La0.04(ZrxTi1-x)0.99O3) with x = 0.52, where
earlier experimental investigation of oxygen vacancies influence on the polar
properties was performed and the evidence of oxygen vacancies induced
ferroelectricity was obtained. Since the oxygen vacancies are known to be
elastic dipoles, they influence upon elastic and electric fields due to Vegard
and flexoelectric coupling. We include the vacancies elastic and
electrostrictive contribution into free energy functional. The calculations of
the vacancies impact on polar properties were performed using their
concentration distribution function. It was shown that the negative Curie
temperature of a relaxor TC* is renormalized by the elastic dipoles due to the
electrostrictive coupling and can become positive at some large enough
concentration of the vacancies. We calculated the local polarization and
electric field induced by the flexo-chemical coupling in dependence on the
concentration of oxygen vacancies. The coexistence of FE phase and relaxor
state can take place because of inhomogeneity of vacancies concentration
distribution.

16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
37
The categories of this paper are: supr-con
23
The categories of this paper are: solv-int
8
The categories of this paper are: hep-ex
36
The categories of this paper are: cmp-lg
19
The categories of this paper are: eess
15
The categories of this paper are: nucl-ex
2
The categories of this paper are: math
0
The categories of this paper are: hep-ph
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
14
The categories of this paper are: math-ph
10
The categories of this paper are: q-bio