Journal article

Publication year: 2024

Journal: physica status solidi (a) – applications and materials science

ISSN: 1862-6300

eISSN: 1862-6319

Open access status: Hybrid

DOI Link: https://doi.org/10.1002/pssa.202300966

Publisher: Wiley

Abstract: 
The investigation of the structural phase transition in the vicinity of the Curie temperature T-c of LiNb1-xTaxO3 crystals is motivated by the expected combination of advantageous high-temperature properties of LiNbO3 and LiTaO3, including high piezoelectric modules and remarkable high-temperature stability, respectively. T-c marks the ultimate limit for exploiting the piezoelectric properties; however, transition-related structural modifications might impact this and other properties even below T-c. Remarkably, the phase transition from the ferroelectric to the paraelectric phase, whose temperature strongly depends on the composition x, shows a significant drop in the activation energy of the electrical conductivity. The magnitude, temperature dependence, and underlying mechanisms of this drop are discussed from a microscopic perspective. Molecular dynamics calculations in the framework of the density functional theory show that substantial displacements of the cations occur below T-c for both the end compounds LiNbO3 and LiTaO3, and might thus affect the electrical conductivity. Above T-c, the migration of lithium ions is presumably facilitated by a shortened diffusion path for the most favorable jump of the lithium ions. Electronic contributions to the conductivity, which become important above 900 K, are explained within the polaronic picture by the formation and migration of free small polarons.

Harvard Citation style: El Azzouzi, F., Klimm, D., Kapp, A., Verhoff, L., Schaefer, N., Ganschow, S., et al. (2024) Evolution of the Electrical Conductivity of LiNb_1-xTa_xO₃ Solid Solutions across the Ferroelectric Phase Transformation, physica status solidi (a) – applications and materials science, Article 2300966. https://doi.org/10.1002/pssa.202300966

APA Citation style: El Azzouzi, F., Klimm, D., Kapp, A., Verhoff, L., Schaefer, N., Ganschow, S., Becker, K., Sanna, S., & Fritze, H. (2024). Evolution of the Electrical Conductivity of LiNb_1-xTa_xO₃ Solid Solutions across the Ferroelectric Phase Transformation. physica status solidi (a) – applications and materials science, Article 2300966. https://doi.org/10.1002/pssa.202300966