Berlin 2015 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 36: Poster Session I

DS 36.85: Poster

Donnerstag, 19. März 2015, 09:30–12:00, Poster A

Nonlinear Dielectric Response of Anisotropically Strained Epitaxial Ferroelectric Films — •Yang Dai, Jürgen Schubert, Eugen Hollmann, and Roger Wördenweber — Peter Grünberg Institute (PGI), Forschungszentrum Jülich, D-52425 Jülich, Germany

Strain can not only strongly modify the electronic characteristics of ferroelectric material, it can also induce interesting partially novel properties in these systems. In this work, the impact of ac and dc electric field and the field orientation on the dielectric properties of anisotropically strained epitaxial SrTiO3 films grown on DyScO3 are examined. The anisotropic lattice mismatch between the SrTiO3 film and DyScO3 leads to different in-plane tensile strain in the different crystalline direction of 0.95% and 1.05%, respectively. As a result, (i) the tensile strain causes an increase of the ferroelectric-dielectric phase transition temperature to Tmax=258 K and Tmax=288 K for small and large tensile strain, respectively. (ii) With increasing amplitude of the ac electric field, the extrinsic contribution to the dielectric permittivity increases nonlinearly, which provides indication on the dynamic and pinning of domain wall. (iii) The dielectric permittivity is strongly suppressed by an additional dc bias electric field for a restricted temperature regime ranging from 180 K to 320 K. The different dielectric responses are discussed in the term of domain wall dynamic and pinning inducing relaxor type models.