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Domain‐scale imaging to dispel the clouds over the thermal depolarization of Bi 0.5 Na 0.5 TiO 3 ‐based relaxor ferroelectrics
Author(s) -
Yin Jie,
Tao Hong,
Liu Gang,
Wu Jiagang
Publication year - 2020
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.16908
Subject(s) - poling , piezoresponse force microscopy , materials science , depolarization , piezoelectricity , ferroelectricity , condensed matter physics , dielectric , thermal , phase (matter) , characterization (materials science) , phase transition , nanoscopic scale , atmospheric temperature range , chemical physics , nanotechnology , physics , thermodynamics , composite material , optoelectronics , medicine , quantum mechanics , endocrinology
Thermal depolarization temperature, T d , of ferroelectric oxides Bi 0.5 Na 0.5 TiO 3 (BNT), where dielectric and piezoelectric signals exhibit remarkable changes, is providing rich research contents but is not well understood yet. Herein, on the domain‐scale, we give the direct and clear real‐space images of thermal depolarization process on BNT‐based complex oxides. As disclosed by the piezoresponse force microscopy (PFM), heating above T d breaks the poling‐induced large‐sized‐oriented domains into smaller sized polar clusters with different orientations, leading to the thermal depolarization phenomenon. Although the poling‐induced domain decays above T d , the broken domains exhibit a rather larger coherence length than that of the incipient labyrinth‐like nano‐domains. During the heating process, BNT possesses a structural transition from the long‐range‐correlated R 3 c ( a − a − a − anti‐phase tilting) to the short‐range‐correlated P 4 bm ( a 0 a 0 c + in‐phase tilting) phase, which should be the fundamental driving force for the fluctuations of poling‐induced large‐sized‐oriented domains. We expect these results will further promote the understanding about the origin of T d in BNT‐based relaxor ferroelectrics, and provide an intuitive method for the characterization of the thermodynamic and kinetic process in this kind of materials.