Growth of congruent-melting lithium tantalate crystal with stoichiometric structure by MgO doping

Shunsuke Fujii, Satoshi Uda, Kensaku Maeda, Jun Nozawa, Haruhiko Koizumi, Kozo Fujiwara, Tomio Kajigaya

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)


Lithium tantalate (LT) is an oxide material whose congruent composition differs from its stoichiometric composition in the Li2O-Ta 2O5 binary system. Ionic species in the LT melt are segregated during crystal growth, even at the congruent composition, which leads to crystallization electromotive force (C-EMF) at the solid-liquid. On the other hand, when a compound has a stoichiometric structure at the congruent composition, such segregation does not occur. By employing a new concept of stoichiometry of a material where the activity of any constituent element could be unity, we developed a new lithium tantalate with MgO doping, cs-MgO:LT (Li2O:Ta2O5:MgO=40.8:50.0:9.2), that is stoichiometric and coincident with the congruent composition. Because of this coincidence, cs-MgO:LT does not yield C-EMF and does not show segregation during growth even for ionic species. A bulk crystal was grown from the melt of the cs-MgO:LT composition via the Czochralski (CZ) method, and it showed excellent compositional homogeneity, proved by the constant distribution of the Curie temperature throughout the crystal.

Original languageEnglish
Pages (from-to)63-66
Number of pages4
JournalJournal of Crystal Growth
Publication statusPublished - 2013


  • A1. Impurities
  • A1. Interfaces
  • A1. Phase diagrams
  • A1. Segregation
  • A3. Growth from melt
  • B1. Oxides

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry


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