Thermal Stability and Non-Linear Optical and Dielectric Properties of Lead-Free K0.5Bi0.5TiO3 Ceramics
Autor: | Piotr Czaja, Elżbieta Szostak, Joanna Hetmańczyk, Piotr Zachariasz, Dorota Majda, Jan Suchanicz, Małgorzata Karolus, Dariusz Bochenek, Katarzyna Osińska, Jarosław Jędryka, Andriy Kityk, Michał Piasecki |
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Jazyk: | angličtina |
Rok vydání: | 2024 |
Předmět: |
lead-free K0.5Bi0.5TiO3 ceramics
ferroelectric materials dielectric permittivity Raman FT-FIR FT-MIR spectroscopies Technology Electrical engineering. Electronics. Nuclear engineering TK1-9971 Engineering (General). Civil engineering (General) TA1-2040 Microscopy QH201-278.5 Descriptive and experimental mechanics QC120-168.85 |
Zdroj: | Materials, Vol 17, Iss 9, p 2089 (2024) |
Druh dokumentu: | article |
ISSN: | 1996-1944 |
DOI: | 10.3390/ma17092089 |
Popis: | Lead-free K0.5Bi0.5TiO3 (KBT) ceramics with high density (~5.36 g/cm3, 90% of X-ray density) and compositional purity (up to 90%) were synthesized using a solid-state reaction method. Strongly condensed KBT ceramics revealed homogenous local microstructures. TG/DSC (Thermogravimetry-differential scanning calorimetry) techniques characterized the thermal and structural stability of KBT. High mass stability (>0.4%) has proven no KBT thermal decomposition or other phase precipitation up to 1000 °C except for the co-existing K2Ti6O13 impurity. A strong influence of crystallites size and sintering conditions on improved dielectric and non-linear optical properties was reported. A significant increase (more than twice) in dielectric permittivity (εR), substantial for potential applications, was found in the KBT-24h specimen with extensive milling time. Moreover, it was observed that the second harmonic generation (λSHG = 532 nm) was activated at remarkably low fundamental beam intensity. Finally, spectroscopic experiments (Fourier transform Raman and far-infrared spectroscopy (FT-IR)) were supported by DFT (Density functional theory) calculations with a 2 × 2 × 2 supercell (P42mc symmetry and C4v point group). Moreover, the energy band gap was calculated (Eg = 2.46 eV), and a strong hybridization of the O-2p and Ti-3d orbitals at Eg explained the nature of band-gap transition (Γ → Γ). |
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