Li, K., Yue, H., Gong, Z., Guo, K., Liu, Z., Xie, B., Mao, P., Yao, K., & Tay, F. E. H. (2025). The mechanism of weakly coupled relaxor ferroelectric properties in Dy-doped BCT ceramics: Insights from first-principles calculations. Ceramics International, 51(19), 29448–29456. https://doi.org/10.1016/j.ceramint.2025.04.149
Abstract:
The crystal structure, electronic properties, and ferroelectric characteristics of Ba0.7Ca0.3TiO3−xDy (x = 0,0.2,0.3,0.4) have been systematically investigated using first-principles calculations and phenomenological Landau-Ginsburg-Devonshire theory. Our findings demonstrated that the Dy-doped system exhibits a more stable structure than its undoped counterpart, attributed to a lower Kuramoto-Sakati (K-S) energy. Notably, the significant positive and negative displacement disparity between Dy and Ti atoms at the B-site along the [001] direction resulted in diminished local dipole moments within the ferroelectric materials, thereby facilitating observable ferroelectric relaxation properties. As the concentration of Dy doping increased, both the intensity of ferroelectric polarization and the depth of the potential well diminished. This reduction in ferroelectric polarization and relaxation behavior can be primarily attributed to the inconsistent displacement of B-site atoms. Meanwhile, the decrease in potential depth is largely due to the enhanced Dy states at the B-site, which weakened the strong hybridization between the Ti 3d and O 2p orbitals, consequently destabilizing the ferroelectric states. Moreover, the density-of-states analysis indicates a reduction in the band gap, driven by the hybridization between the O 2p and Dy 4d orbitals. Notably, the Dy 4f orbitals exhibit significant spin polarization in both spin directions, contributing to the magnetic behavior observed in this system.
License type:
Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)
Funding Info:
This research / project is supported by the A*STAR - Advanced Manufacturing and Engineering (AME) Programmatic Fund
Grant Reference no. : A20G9b0135