High‐Temperature Elastic Moduli of Flux‐Grown α‐GeO2 Single Crystal |
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| Authors: | Dr. Adrien Lignie Dr. Wei Zhou Dr. Pascale Armand Dr. Benoit Rufflé Richard Mayet Jerôme Debray Dr. Patrick Hermet Dr. Bertrand Ménaert Dr. Philippe Thomas Prof. Philippe Papet |
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| Affiliation: | 1. Institut Charles Gerhardt Montpellier, UMR 5253, CNRS‐UM2‐ENSCM‐UM1, C2M, Université Montpellier 2, CC 1504, Place Eugène Bataillon, 34095 Montpellier Cédex 5 (France), Fax: (+33)?467144290;2. Institut Charles Coulomb, UMR 5221 CNRS‐UM2, Université Montpellier 2, CC 069, Place Eugène Bataillon, 34095 Montpellier Cédex 5 (France);3. Science des Procédés Céramiques et de Traitements de Surface, Centre Européen de la Céramique, UMR 6638, 12 Rue Atlantis, 87068 Limoges Cédex (France);4. Institut Néel, Dpt. Matière Condensée, Matériaux et Fonctions, 25 avenue des Martyrs, Batiment F, BP 166, 38042 Grenoble Cédex 9 (France) |
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| Abstract: | From high‐precision Brillouin spectroscopy measurements, six elastic constants (C11, C33, C44, C66, C12, and C14) of a flux‐grown GeO2 single crystal with the α‐quartz‐like structure are obtained in the 298–1273 K temperature range. High‐temperature powder X‐ray diffraction data is collected to determine the temperature dependence of the lattice parameters and the volume thermal expansion coefficients. The temperature dependence of the mass density, ρ, is evaluated and used to estimate the thermal dependence of its refractive indices (ordinary and extraordinary), according to the Lorentz–Lorenz equation. The extraction of the ambient piezoelectric stress contribution, e11, from the C′11–C11 difference gives, for the piezoelectric strain coefficient d11, a value of 5.7(2) pC N?1, which is more than twice that of α‐quartz. As the quartz structure of α‐GeO2 remains stable until melting, piezoelectric activity is observed until 1273 K. |
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| Keywords: | Brillouin spectroscopy elastic constants germanium oxide single crystal X‐ray diffraction |
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