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.

具有高离子传导特性的氧化铋（Bi₂O₃）δ相可通过一系列组分在室温下稳定存在，即通式为(Bi₁₋ₓYₓ)₂O₃（x取值范围为0.1~0.5）。本研究将在300 K至1100 K的温度区间内，对(Bi₀.₈Y₀.₂)₂O₃与(Bi₀.₆Y₀.₄)₂O₃开展非弹性（振动）中子散射以及准弹性中子散射（QENS）谱学测试。(Bi₁₋ₓYₓ)₂O₃体系的离子扩散起始温度约为500 K。我们的从头算分子动力学模拟结果表明，在1000 K条件下，(Bi₀.₇Y₀.₃)₂O₃中的氧扩散速率远高于纯氧化铋。相较于纯Bi₂O₃，针对(Bi₀.₈Y₀.₂)₂O₃与(Bi₀.₆Y₀.₄)₂O₃的研究可更清晰地阐明非化学计量比与结构无序在提升掺杂体系氧原子高扩散系数过程中所发挥的作用。振动谱的测试将有助于表征与离子传导性相关的特定声子模式。