Oxygen Dynamics in Y2O3 doped Bi2O3: (Bi0.8Y0.2)2O3 and (Bi0.6Y0.4)2O3

The high ionic conducting delta-phase of Bi2O3 can be stabilized at ambient temperature in a range of compositions, viz., (Bi1-xYx)2O3 (x=0.1 -0.5). We would measure inelastic (vibrational) as well as quasielastic neutron scattering (QENS) spectra for (Bi0.8Y0.2)2O3 and (Bi0.6Y0.4)2O3 from 300 K to 1100 K. The diffusion in (Bi1-xYx)2O3 starts at a low temperature of around 500 K. Our ab-inito molecular dynamics simulations show that diffusion of oxygen (at 1000 K) in (Bi0.7Y0.3)2O3 is much more than that in Bi2O3. The study of (Bi0.8Y0.2)2O3 and (Bi0.6Y0.4)2O3 would better enable to understand the role of non-stoichiometry and structural disorder in leading to high diffusion coefficient of oxygen atoms in doped compounds in comparison to pure Bi2O3. The measurement of vibrational spectra would help to characterize the specific phonon modes relevant to the ionic conductivity.