Pressure-induced phase transitions in ${\mathrm{Eu}}_2{\left({\mathrm{MoO}}_4\right)}_3$ single crystals were studied by fluorescence spectroscopy in the range of ambient pressure to $10\mathrm{GPa}$. The spectral range investigated was limited to the ${}^{5}D_0\to {}^{7}F_J$, $J=0,1,2$, transitions. First, low temperature data at ambient pressure were collected for assigning spectra. The spectral changes observed with pressure increase were interpreted in terms of consecutive structural transitions, and possible space groups for the corresponding phases are proposed. A comparison between x-ray diffraction and optical spectroscopic data serves to indicate that amorphization in ${\mathrm{Eu}}_2{\left({\mathrm{MoO}}_4\right)}_3$ begins by a disordering of the oxygen sublattice.

• Received 22 September 2003

DOI:https://doi.org/10.1103/PhysRevB.70.094117