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Title: Ergodicity reflected in macroscopic and microscopic field-dependent behavior of BNT-based relaxors

The effect of heterovalent B-site doping on ergodicity of relaxor ferroelectrics is studied using (1 − y)(0.81Bi{sub 1/2}Na{sub 1/2}TiO{sub 3}-0.19Bi{sub 1/2}K{sub 1/2}TiO{sub 3})-yBiZn{sub 1/2}Ti{sub 1/2}O{sub 3} (BNT-BKT-BZT) with y = (0.02;0.03;0.04) as a model system. Both the large- and small-signal parameters are studied as a function of electric field. The crystal structure is assessed by means of neutron diffraction in the initial state and after exposure to a high electric field. In order to measure ferroelastic domain textures, diffraction patterns of the poled samples are collected as a function of sample rotation angle. Piezoresponse force microscopy (PFM) is employed to probe the microstructure for polar regions at a nanoscopic scale. For low electric fields E < 2 kV·mm{sup −1}, large- and small-signal constitutive behavior do not change with composition. At high electric fields, however, drastic differences are observed due to a field-induced phase transition into a long-range ordered state. It is hypothesized that increasing BZT content decreases the degree of non-ergodicity; thus, the formation of long-range order is impeded. It is suggested that frozen and dynamic polar nano regions exist to a different degree, depending on the BZT content. This image is supported by PFM measurements. Moreover, PFM measurements suggest that the relaxation mechanism after removal ofmore » the bias field is influenced by surface charges.« less
Authors:
; ;  [1] ; ; ;  [2] ;  [3] ;  [4]
  1. Institute of Materials Science, Technische Universität Darmstadt, Petersenstraße 23, 64287 Darmstadt (Germany)
  2. Institute for Material Science and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, Universitätsstraße 15, 45141 Essen (Germany)
  3. Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611-6400 (United States)
  4. (United States)
Publication Date:
OSTI Identifier:
22277984
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 115; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BISMUTH COMPOUNDS; CONCENTRATION RATIO; CRYSTAL STRUCTURE; ELECTRIC FIELDS; FERROELECTRIC MATERIALS; MICROSCOPY; MICROSTRUCTURE; NEUTRON DIFFRACTION; PHASE TRANSFORMATIONS; POTASSIUM COMPOUNDS; RELAXATION; ROTATION; SODIUM COMPOUNDS; TEXTURE; TITANATES; ZINC COMPOUNDS