Volume 83, Number 2, July 2008
Article Number 27001
Number of page(s) 4
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 20 June 2008
EPL, 83 (2008) 27001
DOI: 10.1209/0295-5075/83/27001

Polarons in magnetoelectric K3Fe5F15

A. Levstik, C. Filipic, V. Bobnar, G. Tavcar and B. Zemva

Jozef Stefan Institute - P. O. Box 3000, SI-1001 Ljubljana, Slovenia, EU

received 4 March 2008; accepted in final form 27 May 2008; published July 2008
published online 20 June 2008

The ac electrical conductivity of magnetoelectric K3Fe5F15 was investigated as a function of frequency and temperature. While at higher temperatures charge transport is governed by a thermally activated process, at lower temperatures the real part of the complex ac electric conductivity was found to follow the universal dielectric response $\sigma^\prime\propto\nu^{s}$, being typical for hopping or tunnelling of localized charge carriers. A detailed analysis of the temperature dependence of the UDR parameter s in terms of the theoretical model for tunnelling of small polarons revealed that, below 80 K, this mechanism governs the charge transport in the K3Fe5F15 magnetoelectric fluoride system.

72.20.Fr - Low-field transport and mobility; piezoresistance.
73.40.Gk - Tunneling.
71.38.-k - Polarons and electron-phonon interactions.

© EPLA 2008