Raman spectroscopic study of phase stability and anharmonicity in Bi12TiO20

Raman spectroscopic studies on lead-free piezo-electric compound Bi12TiO20 is reported as a function of pressure upto 25 GPa at room temperature. Results indicate that the compound remains in stable crystalline phase upto 25 GPa. Temperature dependent Raman spectroscopic investigations on Bi12TiO20 indicate that the compound is also stable at high temperatures upto 850 K. From measurements of temperature and pressure dependence of Raman mode frequencies, intrinsic anharmonic parameters are calculated for each of the Raman active modes which are useful in modeling of thermodynamic entities. The results are compared with that of analogous compound Bi12SiO20.