Pressure-induced phase transitions in sodium europium carbonate (Na3Eu(CO3)3) and europium-doped yttrium sesquioxide (Y2O3:Eu3+) by time-resolved laser fluorescence spectroscopy

Time-resolved laser fluorescence spectroscopy has been used to investigate pressure-induced phase transitions in Y2O3:Eu3+ and Na3Eu(CO3)3. Na3Eu(CO3)3 shows a reversible structural phase transformation at 10.5 GPa that can be monitored by fluorescence spectroscopy, fluorescence lifetime measurements and X-ray diffraction. The bulk modulus of Na3Eu(CO3)3 was determined to be B=55(2) GPa from synchrotron X-ray diffraction data. The pressure-induced phase transformations of Y2O3:Eu3+ were characterised by fluorescence lifetime measurements of the hypersensitive 5D0→7F2 transition, which allowed us to monitor the pressure-induced increase in the coordination number.