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The Abnormal Optical Property and Room‐Temperature Exchange Bias Behavior in Na‐ and Ru‐Codoped BiFeO 3 Nanoparticles
Author(s) -
Han Yuling,
Liu Weifang,
Xu Xunling,
Guo Minchen,
Zhang Xiongnan,
Wu Ping,
Gao Ju,
Rao Guanghui,
Wang Shouyu
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.14381
Subject(s) - materials science , vacancy defect , doping , analytical chemistry (journal) , oxygen , nanoparticle , band gap , exchange bias , magnetization , condensed matter physics , nanotechnology , crystallography , chemistry , optoelectronics , magnetic field , magnetic anisotropy , organic chemistry , physics , chromatography , quantum mechanics
Bi 0.98 Na 0.02 Fe 1− x Ru x O 3 ( x = 0, 0.01, 0.02) samples were prepared via a sol–gel method. The formation of the desired materials was confirmed using X‐ray diffraction. The tetravalent Ru doping could effectively reduce the number of oxygen vacancy, and subsequently reduce the leakage current. Interestingly, the optical band gap was narrowed gradually in our samples, which seems contradictory with the variation in oxygen vacancy. To better understand this abnormal optical property, the effect of bandwidth was analyzed based on the change in Fe–O bond length and Fe–O–Fe bond angle, and the corresponding phenomenological qualitative model was proposed. The magnetization was increased with Ru substitution. In addition, an exchange bias ( EB ) phenomenon without field cooled process was observed at room temperature for all the samples, which was explained by introducing a core–shell structure model. Moreover, the EB behavior becomes more pronounced at 5 K for 1% Ru‐doped sample.