Local atomic structure modifications around Fe atoms in polycrystalline multiferroic BiFeO3 are studied by Fe K edge x-ray absorption spectroscopy as a function of temperature across the Neel temperature (T-N = 643 K) in order to reveal local structure modifications related to the magnetic transition. This work demonstrates that on crossing T-N the local structure around Fe shows peculiar changes: the Fe-O bond lengths get shorter, the ligand symmetry increases and the Fe-O bond length disorder (sigma(2)) deviates from Debye behaviour. These results suggest that the structural transition at the ferroelectric Curie temperature (T-C = 1103 K) is anticipated by early local rearrangement of the structure starting already at T-N.
Reddy, V.r., Meneghini, C., Kothari, D., Gupta, A., Aquilanti, G. (2012). High temperature extended x-ray absorption fine structure study of multiferroic BiFeO3. JOURNAL OF PHYSICS. CONDENSED MATTER, 24(33) [10.1088/0953-8984/24/33/336005].
High temperature extended x-ray absorption fine structure study of multiferroic BiFeO3
MENEGHINI, CARLO;
2012-01-01
Abstract
Local atomic structure modifications around Fe atoms in polycrystalline multiferroic BiFeO3 are studied by Fe K edge x-ray absorption spectroscopy as a function of temperature across the Neel temperature (T-N = 643 K) in order to reveal local structure modifications related to the magnetic transition. This work demonstrates that on crossing T-N the local structure around Fe shows peculiar changes: the Fe-O bond lengths get shorter, the ligand symmetry increases and the Fe-O bond length disorder (sigma(2)) deviates from Debye behaviour. These results suggest that the structural transition at the ferroelectric Curie temperature (T-C = 1103 K) is anticipated by early local rearrangement of the structure starting already at T-N.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
