Speaker
Mr
Daniel Maslennikov
(University Montpellier 2)
Description
Piezoelectric materials which can be used at very high temperature without degradation are sought for the control system in severe environmental conditions. However, the use of a piezoelectric material at elevated temperature presents many challenges such as possible phase transition, chemical degradation or structural defect propagation which can cancel or drastically decrease the piezoelectric properties. α-quartz, which is quite common piezoelectric material, cannot be used at temperatures higher than 573°C because of phase transition alfa-->beta-quartz occurs. Among the piezoelectric materials, there are potentially powerful piezoelectric materials with α-quartz structure such as: 1) α-GeO2, which has a very wide range of operating temperature (until 1115°C) because its strong structural distortion prevents the transition to beta-quartz-type phase. 2) BaZnO2 – some theoretical calculations showed that such a crystal with α-quartz structure possesses outstanding piezoelectric properties.
So, the main objectives of the work are: development of the experimental conditions to control the seeded crystal growth of α-GeO2 with high crystalline quality by the high temperature flux method; study of the thermal, piezoelectric and dielectric properties of the crystals at different temperatures (up to 700°C); synthesis of pure powder of complex oxide BaZnO2 and following crystal growth by flux-growth method.
Primary author
Mr
Daniel Maslennikov
(University Montpellier 2)
