Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DF: Dielektrische Festkörper

DF 2: Elektrische und optische Eigenschaften II

DF 2.6: Vortrag

Montag, 8. März 2004, 16:30–16:50, H11

Time domain electric field relaxation, accessing the low temperature dependence of the ionic conductivity in Li_3xLa_2/3−xTiO₃ — •Alberto Rivera^1,2, Jacobo Santamaria¹, Carlos Leon¹, Thomas Blochowicz², Catalin Gainaru², and Ernst Roessler² — ¹GFMC, Dpto. Fisica Aplicada III, Universidad Complutense de Madrid, 28040 Madrid, Spain — ²Experimentalphysik II, Universität Bayreuth, 95440 Bayreuth, Germany

The measurements of the modulus in the time domain, that is the relaxation of the electric field at constant dielectric displacement D, presents several advantages over the more spread permittivity technique. In particular, the electric response of ionic conductors can only be probed in the time domain by a modulus experiment. We analyze the dynamics of a fast ionic conductor, namely crystalline Li_0.18La_0.61TiO₃.

We introduce a capacity correction algorithm to obtain the spectra of the electric response from time domain measurements allowing a standard data analysis in the frequency domain. In this way ionic dynamics are investigated in the frequency range 10⁻⁵ − 10² Hz and for conductivity values in the range 10⁻¹⁴ − 10⁻⁸ S/cm. The DC ionic conductivity shows an Arrhenius temperature dependence below 300 K and down to 120 K, in contrast to the non-Arrhenius behavior found at higher temperatures, making it impossible to apply the Vogel-Fulcher-Tammann law.