Berlin 2015 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 13: Ceramics and Applications (DF with KR)

DF 13.3: Vortrag

Mittwoch, 18. März 2015, 12:10–12:30, EB 407

Tuning structure in epitaxial Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ thin films for ferroelectric applications by using miscut substrates — •Michael Mietschke^1,2, Max Hößler^1,3, Stefan Engelhardt^1,2, Sebastian Fähler^1,2, Ludwig Schultz^1,2, and Ruben Hühne¹ — ¹IFW Dresden — ²TU Dresden — ³TU Chemnitz

Ferroelectric materials like lead magnesium niobate - lead titanate (PMN-PT) show a large electrocaloric effect induced by an electrical field during a diffusionless phase transition, which can be used for novel solid state cooling devices. However, the interplay between the microstructure and the ferroelectric properties is not completely understood so far.

Therefore, epitaxial 1-x Pb(Mg_1/3Nb_2/3)O₃- xPbTiO₃ films were grown by pulsed laser deposition on (001)-oriented single crystalline SrTiO₃ (STO) substrates with a miscut angle between 0 and 15 degrees towards the [100] direction. The structural properties in dependence from the miscut angle and the deposition parameters are studied by detailed x-ray diffraction, atomic force microscopy and transmission electron microscopy. Temperature dependent ferroelectric characterization was performed by using La_0.7Sr_0.3Co₃ buffer layers and additional Pt top electrodes on the surface of the PMN-PT layer. Normal ferroelectric as well as relaxor ferroelectric behavior was found in dependence of the PT content. First attempt were made to determine the electrocaloric properties from the temperature dependent polarization curves.