The Metal-Insulator Transition in Y1-xCaxTiO 3 Caused by Phase Separation

K. Kato, E. Nishibori, M. Takata, M. Sakata, T. Nakano, K. Uchihira, M. Tsubota, F. Iga, T. Takabatake

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)

Abstract

In order to explore the origin of the metal-insulator (M-I) transition, the precise crystal structures of the hole-doped Mott insulator system, Y 1-xCaxTiO3 (x = 0.37, 0.39 and 0.41), are studied for the temperature range between 20 K and 300 K by synchrotron radiation (SR) X-ray powder diffraction. For both Y0.63Ca 0.37TiO3 and Y0.61Ca0.39TiO 3 compositions, the orthorhombic (Pbnm) - monoclinic (P2 1/n) structural phase transition occurs at approximately 230 K, which is much higher than their individual M-I transition temperatures, i.e., 60 K and 130 K, respectively. For these compositions, significant phase separation (low-temperature orthorhombic + monoclinic) is also found in the vicinity of the M-I transition temperature. On the other hand, Y 0.59Ca0.41TiO3, which does not exhibit M-I transition and preserves a metallic behavior down to 1.5 K, is in a two phase state from 20 K to 300 K. It is concluded that the existence of the phase separation causes the M-I transition in Y1-xCaxTiO 3, and the low-temperature orthorhombic phase contributes to the metallic property of this system.

Original languageEnglish
Pages (from-to)2082-2085
Number of pages4
Journaljournal of the physical society of japan
Volume71
Issue number9
DOIs
Publication statusPublished - 2002 Sep

Keywords

  • M-I transition
  • Phase separation
  • Phase transition
  • Powder diffraction
  • Rietveld analysis
  • Synchrotron radiation
  • YTiO

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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