OLIVEIRA EVANGELISTA, Renato; CARDINAL, Thierry; FARGIN, Evelyne; BUFFIERE, Sonia; CAM, Nithavong; DUSSAUZE, Marc; RODRIGUEZ, Vincent; ADAMIETZ, Frederic; MARCONDES, Lia; BATISTA, Gislene; CASTRO CASSANJES, Fabia; POIRIER, Gael

doi:10.1016/j.jallcom.2021.160245

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OLIVEIRA EVANGELISTA, Renato
Instituto de Ciência e Tecnologia

CARDINAL, Thierry
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]

FARGIN, Evelyne
Institut de Chimie de la Matière Condensée de Bordeaux [ICMCB]

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Journal of Alloys and Compounds. 2021, vol. 877, p. 160245

Elsevier

Resumen en inglés

Complex sequential crystallization mechanisms were investigated in the glass composition 70GeO2-10Na2O-20Ta2O5 prepared by melt-quenching. In a first stage, a classical volume-nucleated crystallization of sodium tantalate perovskite Na2Ta8O21 is induced under short time heat-treatments whereas longer annealing treatments promote the formation of surface spherical structures known as spherulites. These singular glass-ceramics were deeply investigated by density measurements, differential scanning calorimetry (DSC), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), Auger Electron Spectroscopy (EDS), correlated Raman and second harmonic generation (SHG) microscopy as well as macro-SHG measurements. These surface spherulites with average size up to 50 µm are richer in tantalum but poorer in germanium than the surrounding material. However, measured SHG signals were found to be related to quartz-like α-GeO2 grown inside the spherulites. Therefore these materials exhibit a second-order non-linear optical response, related to the symmetry of the point group D3 given by the quartz GeO2 grown for the first time in a transparent glass-ceramic.< Leer menos

Palabras clave en inglés

α-GeO2

Tantalum

Glass-ceramic

Spherulite

Second harmonic generation

DOI

http://dx.doi.org/10.1016/j.jallcom.2021.160245

Proyecto ANR

Initiative d'excellence de l'Université de Bordeaux - ANR-10-IDEX-0003

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Centros de investigación

Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB) - UMR 5026