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DF: Fachverband Dielektrische Festkörper

DF 15: Dielectric and ferroelectric thin films

DF 15.2: Vortrag

Donnerstag, 29. März 2012, 10:15–10:35, EB 107

Strain effects in ferroelectric thin films: the impact on the switching kinetics of Pb(Zr,Ti)O₃ — •Andreas Herklotz^1,3, Michael D. Biegalski², Hans M. Christen², Ludwig Schultz¹, and Kathrin Dörr³ — ¹IFW Dresden, 01171 Dresden, Germany — ²Oak Ridge National Laboratory, Center for Nanophase Materials Sciences, 37831 Oak Ridge, TN, USA — ³Martin-Luther-Universität Halle-Wittenberg, 06099 Halle, Germany

We present first results on the effect of biaxial strain on the switching of ferroelectric thin films. The strain state of epitaxially grown tetragonal and rhombohedral Pb(Zr,Ti)O₃ films is controlled directly and reversibly by the use of piezoelectric Pb(Mg_1/3Nb_2/3)_0.72Ti_0.28O₃ (001) (PMN-PT) substrates. The ferroelectric switching behavior is investigated by pulsed electric polarization measurements.

At small external electric fields the films show switching characteristics consistent with a creep-like domain wall motion behavior. In this pinning regime we find a huge decrease of the switching time under compressive strain, i.e an acceleration of the switching kinetics. For larger external electric fields the domain wall motion turns into a depinning regime. The strain effect is changing to a moderate positive value, that is, the switching kinetics is slowed down under the influence of compressive in-plane strain. These results are found in tetragonal and rhombohedral films, thus revealing a general behavior that is not governed by the lattice symmetry or the domain pattern.