Vacancy ordering and oxygen dynamics in oxide ion conducting La1−xSrxGa1−xMgxO3−x ceramics: 71Ga, 25Mg and 17O NMR

摘要: The oxygen vacancies distribution in the rigid lattice and thermally activated motion of atoms are studied La{sub 1-x}Sr{sub x}Ga{sub 1-x}Mg{sub x}O{sub 3-x} (x=0.00; 0.05; 0.10; 0.15 0.20) compounds. For that {sup 71}Ga, 25}Mg 17}O NMR was performed from 100 K up to 670 K, ion conductivity measurements were carried out 1273 K. comparison electric field gradients at Ga- Mg-sites evidences appear exclusively near gallium cations as a species trapped below room temperature local clusters, GaO{sub 5/2}-{open_square}-GaO{sub 5/2}. These clusters decay higher into mobile constituents structural octahedra Ga(O{sub 5/6{open_square}1/6}){sub 6/2}. At same time, nearest octahedral environment magnesium persists different doping levels. case two adjacent vacant anion sites is found highly unlikely within range. starts develop above observed both motional narrowing spectra nuclear spin-lattice relaxation rate. obtained results show types exist, slow fast one. former long-rangemore » diffusion whereas latter back forth jumps between sites. strongly differentiated by probability vacancy formation, like apical site occupied equatorial orthorhombic compositions x <0.15. -- Graphical abstract: Up 700 Ga but not Mg. Display Omitted« less