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Formation of anisotropic grains and modified ferroelectric properties in Cr‐doped Bi 5 FeTi 3 O 15 thin films
Author(s) -
Zhang Junyan,
Song Dongpo,
Lee JungKun
Publication year - 2021
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.17944
Subject(s) - aurivillius , materials science , ferroelectricity , coercivity , doping , microstructure , dielectric , analytical chemistry (journal) , grain boundary , thin film , condensed matter physics , composite material , nanotechnology , chemistry , chromatography , physics , optoelectronics
Aurivillius phase Bi 5 Cr x Fe 1− x Ti 3 O 15 (0≤ x ≤1) thin films are prepared by the chemical solution deposition method, and the effect of Cr content on the microstructure, ferroelectric property, and electric transport behavior of Bi 5 Cr x Fe 1− x Ti 3 O 15 films is investigated. X‐ray diffraction analysis shows that all of Bi 5 Cr x Fe 1− x Ti 3 O 15 films are complete solid solution and maintain the Aurivillius structure. The replacement of Fe 3+ with smaller Cr 3+ decreases anisotropy and lattice aspect ratio in a‐b plane, which is minimized at the composition of Bi 5 Cr 0.5 Fe 0.5 Ti 3 O 15 . This changes the grain shape from sphere to plate, and Bi 5 Cr 0.5 Fe 0.5 Ti 3 O 15 film consists of only plate‐like grains. Cr doping increases saturated polarization ( P m ) and decreases coercive field ( E c ). Cr doping increases P m of Bi 5 Cr x Fe 1− x Ti 3 O 15 film to 35 μC/cm 2 , but decreases E c down to 125 kV/cm. A decrease in the lattice aspect ratio of a‐b plane promotes the alignment of ferroelectric dipoles under electric field. The frequency‐dependent dielectric property and the leakage current show that the plate‐like grains of Cr‐rich Bi 5 Cr x Fe 1− x Ti 3 O 15 films suppress the transport of carriers from grains to grains and prevents a dramatic leakage current increase. The results of this study provide a design rule to control the ferroelectricity of Aurivillius phase Bi 5 Cr x Fe 1− x Ti 3 O 15 thin films by modifying the composition and lattice aspect ratio.