https://doi.org/10.1140/epjb/e2010-00004-y
Structural and magnetic phases of Bi1-xAxFeO3-δ (A = Sr, Pb) perovskites
1
Scientific-Practical Material Research Center NAS
Belarus, 220072 Minsk, Belarus
2
Physical-Engineering Institute
of Low Temperatures, 61103 Kharkov, Ukraine
3
Helmholtz-Zentrum-Berlin for Materials and Energy, 14109 Berlin,
Germany
4
Laboratory for Neutron Scattering, Paul Scherrer
Institute and ETH Zurich, Switzerland
5
Joint Institute for Nuclear Research, 141980 Dubna,
Russia
Corresponding author: bushinsky@physics.by
Received:
19
June
2009
Revised:
25
November
2009
Published online:
15
January
2010
The Bi1-xAxFeO3-δ (A = Sr, Pb) systems have been studied using the X-ray, neutron powder diffraction and magnetization measurements in a magnetic field up to 14 T. It was found that around x ~ 0.06 the crystal symmetry changes from a rhombohedral (space group R3c) to pseudo-tetragonal. In the composition range 0.07 ≤ x ≤ 0.14 the phases with different symmetry of the unit cell coexist independent of synthesis conditions. The neutron powder diffraction shows that the iron ions have average oxidation state close to 3+. The magnetic structure for Bi0.5Sr0.5FeO3-δ is found to be G-type antiferromagnetic with magnetic moment of about 3.8 μB/Fe3+. The weak ferromagnetic state due to magnetoelectric interactions was revealed in the lightly doped rhombohedrally distorted compositions. No evidence for a spontaneous magnetization was observed for the pseudo-tetragonal phases. These compositions show irreversible nonlinear magnetization vs. field behavior apparently due to small local deviations from the collinearity of the magnetic moments.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2010