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Origin of Relaxor Behavior in K 1/2 Bi 1/2 TiO 3 – Bi ( Mg 1/2 Ti 1/2 ) O 3 Investigated by Electrical Impedance Spectroscopy
Author(s) -
Hu Binbin,
Zhu Mankang,
Guo Jingjian,
Wang Ying,
Zheng Mupeng,
Hou Yudong
Publication year - 2016
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.14073
Subject(s) - tetragonal crystal system , materials science , perovskite (structure) , phase (matter) , ceramic , dielectric , relaxation (psychology) , crystallography , chemistry , crystal structure , psychology , social psychology , optoelectronics , organic chemistry , composite material
Lead‐free binary K 1/2 Bi 1/2 TiO 3 ‐ Bi ( Mg 1/2 Ti 1/2 ) O 3 ( KBT ‐ BMT ) ferroelectric ceramics with a morphology of dense and evenly sized grains have been prepared by conventional solid oxide reaction route. X‐ray diffraction analysis indicates that all the samples possess pure perovskite structure, and undergo a phase transformation from tetragonal to pseudocubic phase as BMT adds into KBT . Meanwhile, BMT addition brings in the enhancement of the relaxor behavior as revealed by temperature‐dependent dielectric profiles and the P–E loops. The impedance analysis reveals that the relaxation process existing in the ceramics belongs to a localized species. Further, in the frequency‐dependent M ″ (f) spectra, a shoulder response emerges accompanied by a bulk response as suitable amount of BMT is added, and its frequency dependence obeys Vogel–Fulcher relation f = f 0 exp[ ‐ E b / k B ( T ‐ T VF )]. The shoulder response is believed to be the evidence of the existence of the polar nanoregions, which dominate the relaxor behavior of KBT ‐ BMT ceramics.