Crystals 2014, 4(2), 168-189; doi:10.3390/cryst4020168

Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues

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Received: 22 April 2014; in revised form: 11 June 2014 / Accepted: 12 June 2014 / Published: 23 June 2014
(This article belongs to the Special Issue Piezoelectric Crystals)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Using 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.
Keywords: single crystal; GaPO4; GeO2; SiO2; raman; infrared; Brillouin; growth from high temperature solution; differential scanning calorimetry (DSC); X-ray diffraction
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MDPI and ACS Style

Armand, P.; Lignie, A.; Beaurain, M.; Papet, P. Flux-Grown Piezoelectric Materials: Application to α-Quartz Analogues. Crystals 2014, 4, 168-189.

AMA Style

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.

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