Pressure-induced structural phase transition in CaCrO4: Evidence from Raman scattering studies

Raman spectroscopic studies have been carried out on CaCrO4 under pressure up to 26.2GPa at ambient temperature. The Raman spectra showed that CaCrO4 underwent a continuous structural phase transition started near 6GPa, and finished at about 10GPa. It was found that the high-pressure phase could be quenched to ambient conditions. Pressure dependence of the Raman peaks suggested that there existed four pressure regions related to different structural characters. We discussed these characters and inferred that the nonreversible structural transition in CaCrO4, most likely was from a zircon-type (I41∕amd) ambient phase to a scheelite-type high-pressure structure (I41∕a).