Investigation of the high temperature phase transitions in BaFe2O4

γ-BaFe2O4 shows antiferromagnetism and an improper ferroelectricity at room temperature. The latter is caused by the simultaneous presence of two non-polar distortion modes of the FeO4 units, namely the in-plane rotation of such units and the up-up-up-up-up-down ordering of the apical oxygens around the hexagonal cavities. In the proposed experiment we would like to explore the two phase transitions observed at high temperatures (above 1038 K) and characterize the ferroelectric to paraelectric phase transition.