Regensburg 2016 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 29: Topical session: Caloric effects in ferroic materials III - Electrocalorics

MM 29.2: Vortrag

Mittwoch, 9. März 2016, 10:30–10:45, H39

Role of polarization anisotropy in epitaxial PMN-PT thin films for electrocaloric studies — •Michael Mietschke^1,2, O. Mey^1,2, C. Molin³, S. Gebhardt³, P. Chekonin¹, S. Fähler¹, K. Nielsch¹, L. Schultz¹, and R. Hühne¹ — ¹IFW Dresden — ²TU Dresden — ³Fraunhofer IKTS Dresden

A prominent example for electrocaloric (EC) materials are Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ (PMN-PT) compounds, which are typically used for high performance actuator applications due to its outstanding piezoelectric properties. As the structural and functional properties of these materials are well-known they might serve as a suitable model system to study the interplay between microstructure and EC properties. Since ferroic materials exhibit a strong anisotropy, we will probe the role of polarization anisotropy on the ECE by variation of the film orientation. Epitaxial films are a useful tool to analyze this correlation in order to optimize the performance of these materials.

Therefore, epitaxial 0.9PMN-0.1PT films were grown by pulsed laser deposition on (001)-oriented and (111)-oriented SrTiO₃ single crystalline substrates using an epitaxial La_0.7Sr_0.3CoO₃ buffer as bottom electrode and additional Au top electrodes. The structural properties were studied by high resolution XRD, AFM and TEM. The anisotropy of the ferroelectric domain structure was investigated by vertical and lateral piezoresponse force microscopy. The indirect determination of the EC properties was performed by temperature dependent polarization measurements at different electric fields. Funded by SPP 1599.