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MA: Fachverband Magnetismus

MA 11: Posters Magnetism III

MA 11.36: Poster

Wednesday, September 29, 2021, 13:30–16:30, P

Polar oxides: Electrical conductivity of LiNb1-xTaxO3 solid solutions from 400 to 800 °C in air — •Ahsanul Kabir, Vanik Sargsyan, Yuriy Suhak, Stepan Hurskyy, and Holger Fritze — Institute of Energy Research and Physical Technologies, Clausthal University of Technology, Am Stollen 19 B, 38640 Goslar, Germany

The electrical conductivity of lithium niobate-lithium tantalate (LNT, LiNb0.5Ta0.5O3) solid solutions is studied in air at temperatures ranging from 400 to 800 °C. The results were compared with lithium niobate (LN) and lithium tantalate (LT) reference samples grown by the Czochralski method, received from the Institute of Microelectronics Technology and High Purity Materials (IMT), Russia, and Precision Micro-Optics (PMO), USA, respectively. Electrical conductivity was measured by impedance spectroscopy in the frequency range of 1 MHz-1 Hz. Over the studied temperature range, LNT sample displays similar electrical conductivity to LN/LT (IMT), e.g. with a value of 2.9*10-4 S/m at 600 °C. In contrast, LN/LT (PMO) compounds illustrate conductivity that is nearly 2 times higher than that of their counterparts. As noticed, the conductivity follows an Arrhenius relation, uncovering a single thermally activated process. The activation energy ranges from 1.20-1.25 eV which is a typical value for the ionic migration in the lithium niobate family and is governed by mobile lithium (Li) vacancies. This result is consistent with theoretical modeling, which predicts the spontaneous formation of Li vacancies in the band gap for a wide range of Fermi energy values. The research is funded by the German Research Foundation and done within the research unit 5044.