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Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues
AbstractUsing the slow-cooling method in selected MoO3-based fluxes, single-crystals of GeO2 and GaPO4 materials with an α-quartz-like structure were grown at high temperatures (T ≥ 950 °C). These piezoelectric materials were obtained in millimeter-size as well-faceted, visually colorless and transparent crystals. Compared to crystals grown by hydrothermal methods, infrared and Raman measurements revealed flux-grown samples without significant hydroxyl group contamination and thermal analyses demonstrated a total reversibility of the α-quartz ↔ β-cristobalite phase transition for GaPO4 and an absence of phase transition before melting for α-GeO2. The elastic constants CIJ (with I, J indices from 1 to 6) of these flux-grown piezoelectric crystals were experimentally determined at room and high temperatures. The ambient results for as-grown α-GaPO4 were in good agreement with those obtained from hydrothermally-grown samples and the two longitudinal elastic constants measured versus temperature up to 850 °C showed a monotonous evolution. The extraction of the ambient piezoelectric stress contribution e11 from the CD11 to CE11 difference gave for the piezoelectric strain coefficient d11 of flux-grown α-GeO2 crystal a value of 5.7(2) pC/N, which is more than twice that of α-quartz. As the α-quartz structure of GeO2 remained stable up to melting, a piezoelectric activity was observed up to 1000 °C.
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Armand, P.; Lignie, A.; Beaurain, M.; Papet, P. Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues. Crystals 2014, 4, 168-189.View more citation formats
Armand P, Lignie A, Beaurain M, Papet P. Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues. Crystals. 2014; 4(2):168-189.Chicago/Turabian Style
Armand, Pascale; Lignie, Adrien; Beaurain, Marion; Papet, Philippe. 2014. "Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues." Crystals 4, no. 2: 168-189.