Secondary phase formation by liquid immiscibility in Ca3Ta(Ga1−xAlx)3Si2O14 melt

Yuki Honda, Hiromasa Niinomi, Jun Nozawa, Junpei Okada, Satoshi Uda

Research output: Contribution to journalArticle

Abstract

The origin of secondary phase formation in Ca3Ta(Ga1−xAlx)3Si2O14 (CTGAS) single crystal growth from its melt is still controversial. Here we demonstrate that liquid immiscibility in bulk CTGAS melt is responsible for the secondary phase formation by examining other possible candidates, eutectic reaction and incongruent melting. The former and the latter possibilities were denied by the fact that the secondary phase formed even in the early stage of CTGAS single crystal growth using the micro-pulling down (µ-PD) method and that the differential thermal analysis (DTA) demonstrated the congruency of the CTGAS. We analyzed compositions of the secondary phases and the matrix in solidified CTGAS melt varying the ratio of Al to Ga in Ga site and temperature. The electron probe micro-analyzer (EPMA) analysis revealed that three kinds of phases, the ratios of which are equal, existed in the solidified melt and their populations varied depending on the ratio of Al to Ga. We demonstrate that the same ratio of Al to Ga between these three phases regardless of their population can be explained only by the presence of liquid immiscibility in CTGAS melt during growth.

Original languageEnglish
Pages (from-to)117-124
Number of pages8
JournalJournal of Crystal Growth
Volume522
DOIs
Publication statusPublished - 2019 Sep 15

Keywords

  • A1. Growth from melt
  • A1. Phase diagram
  • A1. Phase equilibria
  • A1. Solidification
  • B1. Oxides
  • B2. Piezoelectric materials

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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