Electric-Field-Induced Phase Transformation and Frequency-Dependent Behavior of Bismuth Sodium Titanate-Barium Titanate.

Author(s) Lee, K.Y.; Shi, X.; Kumar, N.; Hoffman, M.; Etter, M.; Checchia, S.; Winter, J.; da Silva, L.Lemos; Seifert, D.; Hinterstein, M.
Journal Materials (Basel)
Date Published 2020 Feb 27

The electric field response of the lead-free solid solution (1-)BiNaTiO-BaTiO (BNT-BT) in the higher BT composition range with = 0.12 was investigated using in situ synchrotron X-ray powder diffraction. An introduced Bi-excess non-stoichiometry caused an extended morphotropic phase boundary, leading to an unexpected fully reversible relaxor to ferroelectric (R-FE) phase transformation behavior. By varying the field frequency in a broad range from 10 up to 10 Hz, BNT-12BT showed a frequency-dependent gradual suppression of the field induced ferroelectric phase transformation in favor of the relaxor state. A frequency triggered self-heating within the sample was found and the temperature increase exponentially correlated with the field frequency. The effects of a lowered phase transformation temperature T, caused by the non-stoichiometric composition, were observed in the experimental setup of the freestanding sample. This frequency-dependent investigation of an R-FE phase transformation is unlike previous macroscopic studies, in which heat dissipating metal contacts are used.

DOI 10.3390/ma13051054
ISSN 1996-1944
Citation Materials (Basel). 2020;13(5).

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