Effect of La3+ ion substitution on the dielectric properties of single-crystalline BaTi2O5

Keiji Shiga, Hirokazu Katsui, Hiroyuki Kakuda, Kazuma Yoshikawa, Jun Tsuneyoshi, Takashi Goto

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

La3+ ion substituted single-crystalline BaTi2O5 (Ba1−xLaxTi2O5−z) was prepared by a floating zone method, and the effect of La3+ ion substitution on the phase composition, microstructure and dielectric properties of Ba1−xLaxTi2O5−z was investigated. Ba1−xLaxTi2O5−z was a single phase of BaTi2O5 and its growth direction was parallel to the b-axis at an La3+ content lower than 0.9 at% (x < 0.009). As the substitution increased from 0 to 0.9 at% La3+, the lattice parameters a and c decreased from 1.6906 to 1.6899 nm and from 0.9411 to 0.9406 nm, respectively, and the Curie temperature decreased from 752 K to 700 K. The complex impedance plane plots of single-crystalline BaTi2O5 at 648 K showed a single semicircle associated with the ferroelectric bulk response at high frequencies and a spike associated with ionic diffusion at low frequencies. In contrast, the complex impedance plane plots of Ba1−xLaxTi2O5−z showed a distorted semicircle at an La3+ content lower than 0.2 at%, while those comprised a distorted semicircle at low frequency below 10 Hz and a part of a small semicircle at high frequency (> 10 Hz) at an La3+ content higher than 0.4 at%, indicating the predominance of electronic conduction. The remanent polarization (Pr) of Ba1−xLaxTi2O5−z at room temperature increased with increasing x and was as high as 7 × 10−2 C m−2 at Ba0.996La0.004Ti2O5−z.

Original languageEnglish
Pages (from-to)15375-15380
Number of pages6
JournalCeramics International
Volume43
Issue number17
DOIs
Publication statusPublished - 2017 Dec 1

Keywords

  • BaTi2O5
  • Ferroelectricity
  • Impedance
  • Ionic conduction
  • Lanthanum ion substitution

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Process Chemistry and Technology
  • Surfaces, Coatings and Films
  • Materials Chemistry

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