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FM: Fachverband Funktionsmaterialien
FM 14: Focus Session: Materials Research in Polar Oxides – From Domain Engineering to Photonic and Electronic Devices II
FM 14.4: Vortrag
Mittwoch, 11. März 2026, 15:45–16:00, BEY/0138
Poling and acoustic characterization of near-stoichiometric Li(Nb,Ta)O3 crystals — •Éva Tichy-Rács1, Stepan Hurskyy1, Steffen Ganschow2, Fatima El Azzouzi1, Holger Fritze1, and Yuri Suhak1 — 1Clausthal University of Technology, Goslar, Germany — 2Leibniz Institut für Kristallzüchtung, Berlin, Germany
Li(Nb,Ta)O3 solid solutions bridge the high Curie temperature of LiNbO3 and the thermal stability of LiTaO3, while maintaining a strong piezoelectric performance, making them attractive for high-temperature sensing and actuation. The intrinsic properties of LiNbO3, LiTaO3 and, consequently, their Li(Nb,Ta)O3 solid solutions are well known to be highly sensitive to lithium stoichiometry. In the present work the acoustic properties of near-stoichiometric LiNb1-xTaxO3 (x=0; 0.45; 1) single crystals are investigated as a function of temperature and time by resonant piezoelectric spectroscopy. The near-stoichiometric compositions were obtained by the vapor transport equilibration (VTE). Subsequently, the samples were electrically poled to ensure a single-domain state. The study shows that acoustic losses in nsLT remain in the range of 10-4–10-3 up to 620 ∘C, i.e., within the ferroelectric phase, and increase monotonically with temperature, though only weakly, with an activation energy of about 0.05 eV. In contrast, nsLN and nsLNT45 exhibit a pronounced loss increase above 600 ∘C, attributed to the conductivity-related relaxation mechanism. Under constant operation at 600 ∘C for 350 h, all samples demonstrate excellent long-term stability, with resonance frequency deviations not exceeding ± 100 ppm of the initial value.
Keywords: lithium niobate-tantalate; VTE; poling; acoustic loss