Berlin 2012 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 1: Focus Session: Conductive Domain Walls

DF 1.1: Invited Talk

Monday, March 26, 2012, 09:30–10:00, EB 107

Conducting 180^∘ domain walls in PZT thin films — •Patrycja Paruch — DPMC, University of Geneva, Geneva, Switzerland

Following the recent discovery of conduction at ferroelectric domain walls in otherwise insulating BiFeO3 thin films, we have investigated Pb(Zr0.2Ti0.8)O3 epitaxial thin films using atomic force microscopy (AFM) techniques to identify new functional properties. 180^∘ domain walls in this material show not only a piezoelectric shear response forbidden by symmetry in the bulk material, but also present a current signal in conductive tip AFM. The observed domain wall conduction is clearly differentiable from polarization switching currents, and shows highly nonlinear and asymmetric current-voltage characterisitics, strong temperature dependence at higher temperatures, and high stability. Potential conduction mechanisms will be discussed, specifically in relation to the asymmetric nature of the electrodes contacting the ferroelectric thin film, and the microscopic structure of the domain walls promoting defect segregation.

ref: J. Guyonnet et al, Adv. Mat. 23, 5377 (2011)