Synthesis and Electrical Properties of the Pyrochlore-type Gd2-yLayZr2O7 Solid Solution
J.A. Díaz-Guillén; M.R. Díaz-Guillén; K.P. Padmasree; J.M. Almanza; A.F. Fuentes; J. Santamaría; C. León. Synthesis and Electrical Properties of the Pyrochlore-type Gd2-yLayZr2O7 Solid Solution . Boletín de la Sociedad Española de Cerámica y Vidrio (ISSN: 0366-3175). 2008, Vol. 47 [3], p. 159-2008.
Different compositions in the pyrochlore-type Gd2-yLayZr2O7 solid solution (0 ≤ y ≤ 1) were prepared at room-temperature by mechanically milling stoichiometric mixtures of the corresponding oxides. Irrespective of their lanthanum content, as-prepared powder samples consist of single-phase anion deficient fluorite materials, although long-range ordering of cations and anion vacancies characteristic of pyrochlores was observed in all cases after firing the samples at 1500°C. Interestingly, activation energy for oxygen migration in the series decreases as La-content increases, from 1.13 eV for Gd2Zr2O7 to 0.81 eV for GdLaZr2O7, whereas ionic conductivity was found to be almost La-content independent, at least for y ≤ 0.8 at T = 500°C and y ≤ 0.4 at T = 800°C. These results are explained in terms of weaker ion-ion interactions in better ordered structures (i.e., as La-content increases) and highlight the importance of structural ordering/disordering in determining the dynamics of mobile oxygen ions
Different compositions in the pyrochlore-type Gd2-yLayZr2O7 solid solution (0 ≤ y ≤ 1) were prepared at room-temperature by mechanically milling stoichiometric mixtures of the corresponding oxides. Irrespective of their lanthanum content, as-prepared powder samples consist of single-phase anion deficient fluorite materials, although long-range ordering of cations and anion vacancies characteristic of pyrochlores was observed in all cases after firing the samples at 1500°C. Interestingly, activation energy for oxygen migration in the series decreases as La-content increases, from 1.13 eV for Gd2Zr2O7 to 0.81 eV for GdLaZr2O7, whereas ionic conductivity was found to be almost La-content independent, at least for y ≤ 0.8 at T = 500°C and y ≤ 0.4 at T = 800°C. These results are explained in terms of weaker ion-ion interactions in better ordered structures (i.e., as La-content increases) and highlight the importance of structural ordering/disordering in determining the dynamics of mobile oxygen ions