Phase transition of Bi5Ti3FeO15 ceramics discovered by Raman spectroscopy and <i>in situ</i> synchrotron XRD under stress field
Mengyun Bian, Ye Yan, Anyang Cui, Kai Jiang, Wei Bai, Hongliang Dong, Bin Chen, Zhigao Hu, Junhao Chu
Abstract
Bi5Ti3FeO15 (BTFO) ceramics have been widely studied as a multiferroic material with some potential applications. However, the effect of the stress field on BTFO ceramics with complex lattice structures is unknown. Here, we use pressure-dependent Raman scattering spectroscopy to study the structure/phase transition of BTFO samples. Because the phonon mode changes significantly, there could be a phase transition in the range of 4.5–14.8 GPa. In order to further prove the occurrence of phase transition, we carried out in situ high-pressure angular dispersion x-ray diffraction (XRD), which clearly proved the structural evolution of BTFO: orthorhombic crystal A21am transformed into tetragonal I4/mmm. Note that the results from the XRD experiment are self-consistent with the data derived from Raman spectroscopy. It provides an effective method to explore the phase transition of complex oxide structures under high pressure.