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Controlled growth of large β‐BaB 2 O 4 crystals based on theoretical guidelines
Author(s) -
Li Zhihua,
Zhang Ran,
Wu Yaohuan,
Tang Bo,
Zhang Guochun
Publication year - 2015
Publication title -
journal of applied crystallography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.429
H-Index - 162
ISSN - 1600-5767
DOI - 10.1107/s1600576715016040
Subject(s) - liquidus , crystal (programming language) , phase diagram , homogeneity (statistics) , crystal growth , materials science , thermodynamics , radius , crystallization , analytical chemistry (journal) , phase (matter) , crystallography , chemistry , optics , physics , mathematics , statistics , computer security , organic chemistry , chromatography , computer science , programming language
The diagram of phase equilibria in the BaB 2 O 4 –NaF system has been used to deduce the relationship between the cooling speed (Δ T ), the pulling speed ( v ), the crystal radius ( R s ), the slope of liquidus ( m ), the solution component ( x ) and the total quantity of melt, namely Δ T = 0.00159 R s 2 v m x 2 / G . The theoretical curves of the crystal thickness dependence on cooling rate and pulling rate have also been drawn. Under the guidance of the deduced formulas, the controlled growth of β‐BaB 2 O 4 (BBO) crystals to a desired size has been achieved. A typical as‐grown BBO crystal with dimensions of Ø76 × 33 mm (525.25 g) has been grown successfully by using the high‐temperature top‐seeded solution growth method. The measured optical homogeneity indicates that the as‐grown BBO crystal has high optical quality (Δ n ≃ 6.9 × 10 −6 ). The experimental curves of the crystal thickness versus the cooling rate and pulling rate were in line with the theoretical curves. The phenomenon of diameter shrinkage in the crystal growth has also been explained according to theory and practice. The theoretical derivation and experimental results provide the rationale for further growth of large BBO crystals with high optical quality.