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Title: Cyclic electric field response of morphotropic Bi{sub 1/2}Na{sub 1/2}TiO{sub 3}-BaTiO{sub 3} piezoceramics

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.4922145· OSTI ID:22423743
 [1];  [2];  [3];  [4]; ;  [5];  [6]
  1. School of Materials Science and Engineering, UNSW Australia, 2052 Sydney (Australia)
  2. Institute for Applied Materials, Karlsruhe Institute of Technology, P.O. Box 3640, 76021 Karlsruhe (Germany)
  3. Heinz Maier Leibnitz Zentrum (MLZ), Technische Universität München, 85747 Garching (Germany)
  4. School of Materials Science and Engineering, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of)
  5. Department of Materials and Geoscience, Technische Universität Darmstadt, 64287 Darmstadt (Germany)
  6. School of Mechanical and Manufacturing Engineering, UNSW Australia, 2052 Sydney (Australia)

In this study, the evolution of field induced mechanisms in lead-free piezoelectric ceramics (1−x)Bi{sub 1/2}Na{sub 1/2}TiO{sub 3}-xBaTiO{sub 3} with x = 0.06 and 0.07 was investigated by transmission electron microscopy, neutron, and X-ray diffraction. Preliminary investigations revealed a strong degradation of macroscopic electromechanical properties within the first 100 bipolar electric cycles. Therefore, this structural investigation focuses on a comparative diffraction study of freshly prepared, poled, and fatigued specimens. Transmission electron microscopy and neutron diffraction of the initial specimens reveal the coexistence of a rhombohedral and a tetragonal phase with space group R3c and P4bm, respectively. In situ electric field X-ray diffraction reveals a pronounced field induced phase transition from a pseudocubic state to a phase composition of significantly distorted phases upon poling with an external electric field of 4 kV/mm. Although the structures of the two compositions are pseudocubic and almost indistinguishable in the unpoled virgin state, the electric field response shows significant differences depending on composition. For both compositions, the application of an electric field results in a field induced phase transition in the direction of the minority phase. Electric cycling has an opposite effect on the phase composition and results in a decreased phase fraction of the minority phase in the fatigued remanent state at 0 kV/mm.

OSTI ID:
22423743
Journal Information:
Applied Physics Letters, Vol. 106, Issue 22; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
Country of Publication:
United States
Language:
English