Growth morphology of tetragonal ABCO4 compounds : theory and observations on Czochralski grown crystals
In: Journal of crystal growth, Jg. 171 (1997), Heft 3-4, S. 392-400
academicJournal
- print, 17 ref
Zugriff:
Tetragonal ABCO4 compounds, where A = Sr, Ca, B = rare earth elements and C = Ga or Al, are potential substrate candidates for high-frequency superconducting films. The Hartman-Perdok theory (HPT) explains the relation between crystal structure and morphology and provides the atomic surface topology of the crystalline interface. Theoretical growth forms can be constructed from computed attachment energies, Eahkl, which is assumed to be directly proportional to the growth rate for F faces. HPT has been applied to CaYAlO4 as a model for all ABCO4 compounds with a K2NiF4 crystal structure. F forms are {002}, {101}, {103}, {110}, {112}, {200}, {211} and {213}. The theoretical growth form is planar following {001} with {101} and {110} as lateral forms. At lower effective charges on oxygen, qo, the growth forms are still tabular, but the order of importance of lateral forms changes as function of qo. When the ions on the slice boundaries are ordered, (110) will be absent for the model with the formal charges and replaced by (112) in the case of models with less negative oxygen charges. As-grown crystals show often inhomogeneities in color parallel to the {110} interface. This can be explained by the surface topology of {110}.
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Growth morphology of tetragonal ABCO4 compounds : theory and observations on Czochralski grown crystals
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Autor/in / Beteiligte Person: | WOENSDREGT, C. F ; JANSSEN, H. W. M ; GLOUBOKOV, A ; PAJACZKOWSKA, A |
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Zeitschrift: | Journal of crystal growth, Jg. 171 (1997), Heft 3-4, S. 392-400 |
Veröffentlichung: | Amsterdam: Elsevier, 1997 |
Medientyp: | academicJournal |
Umfang: | print, 17 ref |
ISSN: | 0022-0248 (print) |
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