Synthesis and electrical properties of Sr- and Nb-cosubstituted Bi4-xSrxTi3-xNbxO12 polycrystalline thin films

Hirofumi Matsuda, Takashi Iijima, Hiroshi Uchida, Isao Okada, Takayuki Watanabe, Hiroshi Funakubo, Minoru Osada, Masato Kakihana

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3 Citations (Scopus)

Abstract

Lead-free ferroelectric Bi4Ti3O12 (BIT) thin films were modified by the cosubstitution of Sr2+ for Bi3+ and of Nb5+ for Ti4+ by spin-coating and decomposition of chemical solutions of metal-alkoxide materials (the nominal compositions of Bi4-xSrxTi3-xNbxO12 (BSTN) are x = 0.5, 1.0, 1.5). Single-phase thin films with a BIT-type structure were crystallized above 550°C. At room temperature, the ferroelectric and dielectric properties were found to be Pr = 10 μC/cm2, Ec = 100 kV/cm, εr = 300, and tan δ < 5% for x = 0.5 after annealing at 650°C. The films with x = 1.0 and 1.5 did not exhibit ferroelectric hysteresis behavior because of the decrease in Curie temperature (Tc) below room temperature. The x dependence of of Tc was studied by considering the soft mode behavior in Raman scattering spectra and the Tc values were 400, -25, and -220°C for x = 0.5, 1.0, and 1.5, respectively. The cosubstitution by Sr2+ and Nb5+ is effective for reducing ferroelectric interaction between electrical dipoles leading to a large shift in Tc. Because of its high solubility of Sr2+ and Nb5+ and efficiency for shifting Tc, the BSTN system may find a novel application as a dielectric material rather than as a ferroelectric material.

Original languageEnglish
JournalJapanese Journal of Applied Physics, Part 2: Letters
Volume42
Issue number8 A
Publication statusPublished - 2003 Aug 1
Externally publishedYes

Keywords

  • Bismuth-layer-structured ferroelectrics
  • Chemical solution deposition
  • Crystallization temperature
  • Dielectric property
  • Ferroelectric property
  • Shift of Curie temperature

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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    Matsuda, H., Iijima, T., Uchida, H., Okada, I., Watanabe, T., Funakubo, H., Osada, M., & Kakihana, M. (2003). Synthesis and electrical properties of Sr- and Nb-cosubstituted Bi4-xSrxTi3-xNbxO12 polycrystalline thin films. Japanese Journal of Applied Physics, Part 2: Letters, 42(8 A).