Pressure-induced phase transition of Fe2TiO4: X-ray diffraction and Mössbauer spectroscopy

X-ray diffraction and Mössbauer spectroscopy were employed to investigate structural stability of Fe2TiO4 under high pressure. Measurements were performed up to about 24 GPa at room temperature using diamond anvil cell. Experimental results demonstrate that Fe2TiO4 undergoes a series of phase transitions from cubic (Fd3-bar m) to tetragonal (I41/amd) at 8.7 GPa, and then to orthorhombic structure (Cmcm) at 16.0 GPa. The high-pressure phase (Cmcm) of Fe2TiO4 is kept on decompression to ambient pressure. In all polymorphs of Fe2TiO4, iron cations present a high-spin ferrous property without electric charge exchange with titanium cations at high pressure supported by Mössbauer evidences. - Graphical abstract: A series of phase transition of Fe2TiO4 occurs from cubic (a) to tetragonal (b and c) then to orthorhombic phase (d–f) at high pressure. Highlights: ► High pressure behaviors of Fe2TiO4 were investigated. ► Phase transitions were observed from cubic to tetragonal and then to orthorhombic. ► Orthorhombic phase can be kept on decompression. ► In all polymorphs of Fe2TiO4, iron ions are ferrous with high-spin state.