Sol-gel route to ferroelectric layer-structured perovskite SrBi2Ta2O9 and SrBi2Nb2O9 thin films

Kazumi Kato, Can Zheng, Jeffrey M. Finder, Sandwip Dey, Yasuyoshi Torii

Research output: Contribution to journalArticlepeer-review

155 Scopus citations

Abstract

Precursors for layer-structured perovskite thin films of SrBi2Ta2O9 (SBT) and SrBi2Nb2O9 (SBN) were prepared by the reactions of a strontium-bismuth double methoxyethoxide and tantalum or niobium methoxyethoxide in methoxyethanol, followed by partial hydrolysis. Several spectroscopic techniques, such as 1H-, 13C-, and 93Nb-NMR (nuclear magnetic resonance), and Fourier-transform infrared spectroscopy were used to analyze the arrangement of the metals and oxygen in the precursor molecules. The precursors contained Sr-O-M (where M is Ta or Nb) bonds (i.e., a strontium is connected to two MO6 octahedra) and Sr-O-Bi bonds with a bismuth atom bonded to the oxygens of the MO6 octahedron. The arrangement of metals and oxygens was considered to be similar to the layer-structured perovskite crystal sublattice. As a result, the sol-gel-derived SBT thin films crystallized, by rapid thermal annealing in an oxygen atmosphere below 550°C, and they exhibited preferred (115) orientation. The crystallinity improved and the crystallite size increased with temperature up to 700°C. In the case of SBN thin films, a low heating rate (2°C/min) was necessary for the control of the crystallographic (115) orientation, whereas a rate of 200°C/s (rapid thermal annealing) produced films that exhibited c-axis orientation. The (115) SBT thin film, heated to 700°C, exhibited improved ferroelectric properties.

Original languageEnglish (US)
Pages (from-to)1869-1875
Number of pages7
JournalJournal of the American Ceramic Society
Volume81
Issue number7
DOIs
StatePublished - Jul 1998

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry

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