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Engineering of Self‐Assembled Domain Architectures with Ultra‐high Piezoelectric Response in Epitaxial Ferroelectric Films
Author(s) -
Ouyang J.,
Slusker J.,
Levin I.,
Kim D.M.,
Eom C.B.,
Ramesh R.,
Roytburd A. L.
Publication year - 2007
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.200600823
Subject(s) - materials science , ferroelectricity , piezoelectricity , condensed matter physics , phase boundary , piezoelectric coefficient , epitaxy , tetragonal crystal system , substrate (aquarium) , thin film , piezoresponse force microscopy , phase (matter) , crystallography , nanotechnology , dielectric , optoelectronics , crystal structure , composite material , physics , layer (electronics) , chemistry , oceanography , geology , quantum mechanics
Substrate clamping and inter‐domain pinning limit movement of non‐180° domain walls in ferroelectric epitaxial films thereby reducing the resulting piezoelectric response of ferroelectric layers. Our theoretical calculations and experimental studies of the epitaxial PbZr x Ti 1– x O 3 films grown on single crystal SrTiO 3 demonstrate that for film compositions near the morphotropic phase boundary it is possible to obtain mobile two‐domain architectures by selecting the appropriate substrate orientation. Transmission electron microscopy, X‐ray diffraction analysis, and piezoelectric force microscopy revealed that the PbZr 0.52 Ti 0.48 O 3 films grown on (101) SrTiO 3 substrates feature self‐assembled two‐domain structures, consisting of two tetragonal domain variants. For these films, the low‐field piezoelectric coefficient measured in the direction normal to the film surface ( d 33 ) is 200 pm V –1 , which agrees well with the theoretical predictions. Under external AC electric fields of about 30 kV cm –1 , the (101) films exhibit reversible longitudinal strains as high as 0.35 %, which correspond to the effective piezoelectric coefficients in the order of 1000 pm V –1 and can be explained by elastic softening of the PbZr x Ti 1– x O 3 ferroelectrics near the morphotropic phase boundary.