Novel high pressure phase evolution in PbRhO3+x

We propose an investigation of the pressure dependent evolution of PbRhO3+x structures between 14 and 24 GPa under stoichiometric and excess oxygen conditions. This is carried out in order to elucidate the transformation mechanisms between three newly synthesised PbRhO3+x phases; pyrochlore Pb2Rh2O7, YMnO3 type PbRhO3 and perovskite PbRhO3. A pyrochlore → YMnO3 type → perovskite pressure dependent phase sequence has not been reported in other systems. The understanding of this mechanism has implications for pressure dependent ABO3 phase relationships as well as the stabilisation mechanisms of YMnO3 type compounds, an attractive structure type for multiferroic materials.