Ionic Conductivity of Apatite-type Rare-earth Silicates Prepared by Mechanical Milling
L.G. Martínez-González; E. Rodríguez-Reyna; K.J. Moreno; J.I. Escalante-García; A.F. Fuentes. Ionic Conductivity of Apatite-type Rare-earth Silicates Prepared by Mechanical Milling. Journal of Alloys and Compounds (ISSN 0925-8388). 2009, Vol. 476, p. 710-2009.
<p>Apatite-type silicates, RE10-x(SiO4)6O’2+y (RE = La, Nd, Gd and Dy), can be prepared by mechanical milling (MM) starting from stoichiometric mixtures of the constituent oxides, RE2O3 and SiO2. XRD patterns collected after grinding the starting mixtures in a planetary ball mill for 9 hrs contain only the characteristic reflections of the target materials. The electrical properties were analyzed on sintered pellets by using impedance spectroscopy and the isothermal conductivity data were successfully fitted to a Jonscher-type empirical expression with a decreasing fractional exponent n as the RE3+ cation size increases. Activation energies for oxygen migration were found to decrease and conductivity to increase as the size of the RE3+ cation increases with the highest conductivity values obtained for the apatite-type lanthanum silicate. In addition, we also show that the electrical properties of the as-prepared materials are influenced by the silicon source used in their synthesis</p>
<p>Apatite-type silicates, RE10-x(SiO4)6O’2+y (RE = La, Nd, Gd and Dy), can be prepared by mechanical milling (MM) starting from stoichiometric mixtures of the constituent oxides, RE2O3 and SiO2. XRD patterns collected after grinding the starting mixtures in a planetary ball mill for 9 hrs contain only the characteristic reflections of the target materials. The electrical properties were analyzed on sintered pellets by using impedance spectroscopy and the isothermal conductivity data were successfully fitted to a Jonscher-type empirical expression with a decreasing fractional exponent n as the RE3+ cation size increases. Activation energies for oxygen migration were found to decrease and conductivity to increase as the size of the RE3+ cation increases with the highest conductivity values obtained for the apatite-type lanthanum silicate. In addition, we also show that the electrical properties of the as-prepared materials are influenced by the silicon source used in their synthesis</p>