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Relaxor Behavior and Large Room‐Temperature Polarization of Ferroelectric Sr 4 CaBiTi 3 Nb 7 O 30 Ceramics
Author(s) -
Gong Gaoshang,
Zerihun Gebru,
Fang Yujiao,
Huang Shuai,
Yin Chongyang,
Yuan Songliu
Publication year - 2015
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.13256
Subject(s) - ferroelectricity , materials science , dielectric , curie temperature , raman spectroscopy , condensed matter physics , ceramic , phase transition , analytical chemistry (journal) , polarization (electrochemistry) , microstructure , nuclear magnetic resonance , optics , optoelectronics , chemistry , ferromagnetism , composite material , physics , chromatography
A new relaxor ferroelectric ceramics, Sr 4 CaBiTi 3 Nb 7 O 30, were prepared. The microstructure, morphology, dielectric, and ferroelectric properties were studied. The ceramics were found that growing in some directions preferentially. Two dielectric relaxations were observed below the Burns temperature T B = 460 K and relaxation‐I can be described by the Vogel–Fulcher law. The Curie–Weiss constant ( C ) of 1.33 × 10 5 K confirms the displacive‐type ferroelectric phase transition. The ceramics exhibit the first‐order diffuse ferroelectric phase transition feature. The diffusion exponent varies from 1.99 to 1.92 with different applied frequencies. Room‐temperature ( RT ) polarization was evaluated, and P r = 2.6 μC/cm 2, E c = 15.2 kV/cm values were obtained. The high breakdown voltage (≥80 kV/cm) and low leakage current confirmed the high quality of Sr 4 CaBiTi 3 Nb 7 O 30 ceramics. All of these features suggest that Sr 4 CaBiTi 3 Nb 7 O 30 may be used to substitute lead‐based relaxor ferroelectric materials for environmental friendly. Raman spectra and polarization measured at different temperatures attribute the high‐ and low‐temperature dielectric relaxation to flipping and breathing of polar nanoregions, respectively.