Search for new modulations in the BiFeO3 structure: SR diffraction and Mِssbauer studies

High resolution synchrotron radiation (SR) diffraction does not show any sign of charge ordering nor any crystal symmetry breaking in BiFeO3 at temperatures from 5 K up to 1000 K. The temperature dependence of the BiFeO3 lattice parameters shows a local minimum of the rhombohedral angle α r h around T N suggesting a strong spin–lattice coupling. Mössbauer spectroscopy studies support the magnetic modulation of the hyperfine fields observed by NMR which are related to the modulated Fe3+ magnetic moments ordering observed by neutron diffraction.