Effect of interface electric field on partitioning during the growth of conventional and true congruent-melting LiNbO3 crystals

Qilin Shi, Jun Nozawa, Satoshi Uda

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Doping of 4.7 mol% MgO into LiNbO3 (LN) with 50 mol% Nb2O5 enables it to be simultaneously stoichiometric and congruent (denoted as cs-MgO:LN). The equilibrium partitioning coefficient, k0, is unity; therefore, it is expected that no segregation of any ionic species occurs during crystal growth, and thus cs-MgO:LN is regarded as a true congruent-melting material. However, the segregation of ionic species was experimentally observed during the growth of a cs-MgO:LN crystal grown by the micro-pulling down (μ-PD) technique because of the formation of an intrinsic interface electric field related to the Seebeck effect caused by a high temperature gradient near the solid–liquid interface, thus changing k0 to non-unity. An external current was injected into the solid–liquid interface to compensate the intrinsic electric field and it was experimentally shown that the true congruent-melting state of cs-MgO:LN was achieved, which was confirmed by a homogenous Mg distribution near the interface that led to a k0 of unity for all constituent species, including ionic species. The relationship between the melt and the growing LN crystal is revealed to be a metal-n type semiconductor junction.

Original languageEnglish
Article number125864
JournalJournal of Crystal Growth
Volume549
DOIs
Publication statusPublished - 2020 Nov 1

Keywords

  • A1. Growth models
  • A1. Impurities
  • A1. Segregation
  • A2. Crystallization electromotive force
  • A2. Growth from melt
  • B1. Oxides

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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