TY - JOUR
T1 - Growth of congruent-melting lithium tantalate crystal with stoichiometric structure by MgO doping
AU - Fujii, Shunsuke
AU - Uda, Satoshi
AU - Maeda, Kensaku
AU - Nozawa, Jun
AU - Koizumi, Haruhiko
AU - Fujiwara, Kozo
AU - Kajigaya, Tomio
N1 - Funding Information:
This work was supported in part by JSPS KAKENHI Grant number 24360002 .
PY - 2013
Y1 - 2013
N2 - 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.
AB - 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.
KW - A1. Impurities
KW - A1. Interfaces
KW - A1. Phase diagrams
KW - A1. Segregation
KW - A3. Growth from melt
KW - B1. Oxides
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U2 - 10.1016/j.jcrysgro.2013.08.020
DO - 10.1016/j.jcrysgro.2013.08.020
M3 - Article
AN - SCOPUS:84884201478
SN - 0022-0248
VL - 383
SP - 63
EP - 66
JO - Journal of Crystal Growth
JF - Journal of Crystal Growth
ER -