Structural stability and phonon anharmonicity of Y2MoO6: Raman spectroscopic and XRD studies

As one promising host material for inorganic phosphors, structural stability and vibrational properties of monoclinic Y2MoO6 have been studied using in situ synchrotron X-ray diffraction and Raman spectroscopy up to 34.5 GPa and over 120-660 K temperature range, respectively. The results show that Y2MoO6 does not undergo any phase transition at above pressure and temperature ranges. Its isothermal bulk modulus is found to be 143.8 GPa, implying that this compound is highly incompressible. From measurements of temperature and pressure dependence of Raman mode frequencies, thermodynamic Grüneisen parameters and intrinsic anharmonic parameters are calculated for each Raman active mode, which are useful in modeling of thermodynamic entities. The result shows that the temperature dependencies of the phonon frequencies are well described by considering the contributions from thermal expansion and lattice anharmonicity.