Europhys. Lett.
Volume 69, Number 5, March 2005
Page(s) 770 - 776
Section Condensed matter: structure, mechanical and thermal properties
Published online 04 February 2005
Europhys. Lett., 69 (5), pp. 770-776 (2005)
DOI: 10.1209/epl/i2004-10419-7

Effects of reduced dimensionality in the relaxation dynamics of ionic conductors

M. Castro1, A. Rivera2, J. García-Barriocanal2, F. Domínguez-Adame3, A. G. Belous4, J. Santamaría2 and C. León2

1  GISC, Escuela Técnica Superior de Ingeniería (ICAI) Universidad Pontificia Comillas - 28015 Madrid, Spain
2  GFMC, Departamento de Física Aplicada III, Universidad Complutense 28040 Madrid, Spain
3  GISC, Departamento de Física de Materiales, Universidad Complutense 28040 Madrid, Spain
4  Institute of Inorganic Chemistry, Ukrainian Academy of Sciences 252680, Ukraine

received 2 November 2004; accepted in final form 3 January 2005
published online 4 February 2005

We report on the dispersive ionic conductivity in $\chem{Li}$0.5-x$\chem{Na}$x $\chem{La_{0.5}TiO_{3}}$ ( $0\leq
x\leq 0.5$), where the number of available positions for the mobile $\chem{Li}$ ions is reduced by introducing immobile $\chem{Na}$ ions. At high frequency the conductivity is power law dependent with an exponent which increases as the number of accessible neighboring sites decreases. This result is quantitatively accounted for in terms of a one-parameter statistical microscopic model. We provide experimental and theoretical evidence for the importance of reduced dimensionality resulting from the blocked pathways in slowing down the dynamics of diffusing ions.

66.30.Hs - Self-diffusion and ionic conduction in nonmetals.
66.10.Ed - Ionic conduction.

© EDP Sciences 2005