Effect of Ho Content on Microstructure and Ferroelectric Properties of Bi4−xHoxTi3O12 Thin Films Prepared by Sol–Gel Method

Authors

  • Dongyun Guo,

    Corresponding author
    1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
    2. Department of Physics, Wuhan University, Wuhan 430072, China
      †Authors to whom correspondence should be addressed. e-mail: guody@public.wh.hb.cn; lmzhang@whut.edu.cn
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  • Lianmeng Zhang,

    Corresponding author
    1. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070, China
      †Authors to whom correspondence should be addressed. e-mail: guody@public.wh.hb.cn; lmzhang@whut.edu.cn
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  • Meiya Li,

    1. Department of Physics, Wuhan University, Wuhan 430072, China
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  • Jun Liu,

    1. Department of Physics, Wuhan University, Wuhan 430072, China
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  • Benfang Yu

    1. Department of Physics, Wuhan University, Wuhan 430072, China
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  • R. E. Riman—contributing editor

  • This work was financed by the Hubei Province Natural Science Foundation (Contract No. 2007ABA309).

  • Authors to whom correspondence should be addressed. e-mail: guody@public.wh.hb.cn; lmzhang@whut.edu.cn

Abstract

Bi4−xHoxTi3O12 (BHT-x) thin films with Ho content x=0.2, 0.4, 0.6, 0.8, and 1.0 were prepared on Pt/Ti/SiO2/Si substrates by a sol–gel method. Effects of Ho contents on the microstructure and ferroelectric properties of BHT-x thin films were investigated. All the BHT-x samples consist of the Bi-layered Aurivillius phase. The lattice constants along the a, b, and c axes decrease with the increase of x. The remanent polarization (2Pr) and dielectric constant (ɛr) increase firstly and then decreases with the increase of the Ho content, while the leakage current density shows opposite trend. BHT-0.4 film exhibits the best electrical properties with 2Pr 44.2 μC/cm2, 2Ec 323.7 kV/cm, ɛr 489 (at 1 MHz), dielectric loss 0.018 (at 1 MHz), leakage current density 8.0 × 10−8 A/cm2 (under 200 kV/cm), as well as the strongest fatigue resistance (the polarization loss is only 3% after 4.46 × 109 switching cycles).

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