Temperature-dependent Raman spectra of Bi2Sn2O7 ceramics

The Bi2Sn2O7 pyrochlore is known to undergo a sequence of structural phase transitions with an increase in temperature. Raman spectroscopy was employed in the investigation of the temperature dependence of the active phonons in the Raman spectrum. We observed 19 broad modes at room temperature, reflecting the low symmetry of the α-phase of Bi2Sn2O7. The modes were discussed in relation to the Raman spectra of other pyrochlore-based oxides. The temperature dependence of the phonons evidences the α → β structural phase transition observed near 127 °C.