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

Dittmer, Robert and Gobeljic, Danka and Jo, Wook and Shvartsman, Vladimir V. and Lupascu, Doru C. and Jones, Jacob L. and Rödel, Jürgen (2014):
Ergodicity reflected in macroscopic and microscopic field-dependent behavior of BNT-based relaxors.
In: Journal of Applied Physics, pp. 084111(1-10), 115, (8), ISSN 0021-8979, [Online-Edition: http://dx.doi.org/10.1063/1.4867157],
[Article]

Abstract

The effect of heterovalent B-site doping on ergodicity of relaxor ferroelectrics is studied using (1 − y)(0.81Bi1/2 Na 1/2TiO3-0.19Bi1/2K1/2TiO3)-yBiZn1/2Ti1/2O3 (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−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 of the bias field is influenced by surface charges.

Item Type: Article
Erschienen: 2014
Creators: Dittmer, Robert and Gobeljic, Danka and Jo, Wook and Shvartsman, Vladimir V. and Lupascu, Doru C. and Jones, Jacob L. and Rödel, Jürgen
Title: Ergodicity reflected in macroscopic and microscopic field-dependent behavior of BNT-based relaxors
Language: English
Abstract:

The effect of heterovalent B-site doping on ergodicity of relaxor ferroelectrics is studied using (1 − y)(0.81Bi1/2 Na 1/2TiO3-0.19Bi1/2K1/2TiO3)-yBiZn1/2Ti1/2O3 (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−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 of the bias field is influenced by surface charges.

Journal or Publication Title: Journal of Applied Physics
Volume: 115
Number: 8
Uncontrolled Keywords: Atomic force microscopy; Piezoelectric fields; Relaxor ferroelectrics Polarization; Electric fields; Neutron diffraction; Crystal structure; Electric measurements; Electrical properties; Sodium
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Nonmetallic-Inorganic Materials
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis > Subproject A1: Manufacturing of ceramic, textured actuators with high strain
11 Department of Materials and Earth Sciences > Material Science
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue > A - Synthesis
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres > CRC 595: Electrical fatigue
11 Department of Materials and Earth Sciences
Zentrale Einrichtungen
DFG-Collaborative Research Centres (incl. Transregio) > Collaborative Research Centres
DFG-Collaborative Research Centres (incl. Transregio)
Date Deposited: 28 Feb 2014 10:15
Official URL: http://dx.doi.org/10.1063/1.4867157
Additional Information:

SFB 595 A1

Identification Number: doi:10.1063/1.4867157
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