| Autor: |
Koroleva MS; Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar 167982, Russia., Ishchenko AV; Ural Federal University, NANOTECH Center, Ekaterinburg 620002, Russia., Vlasov MI; Ural Federal University, NANOTECH Center, Ekaterinburg 620002, Russia.; Institute of High Temperature Electrochemistry, Ural Branch, Russian Academy of Sciences, Ekaterinburg 620137, Russia., Krasnov AG; Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar 167982, Russia., Istomina EI; Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar 167982, Russia., Shein IR; Institute of Solid State Chemistry, Ural Branch, Russian Academy of Sciences, Ekaterinburg 620990, Russia., Weinstein IA; Ural Federal University, NANOTECH Center, Ekaterinburg 620002, Russia.; Institute of Metallurgy, Ural Branch, Russian Academy of Sciences, Ekaterinburg 620016, Russia., Piir IV; Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar 167982, Russia. |
| Abstrakt: |
Eu-doped bismuth-based Bi 1.5 M 0.4 Mg 0.5 Nb 1.5 O 7-δ ( M = Li and Na) pyrochlores were synthesized by the organic-inorganic precursor combustion technique. The study examined the effect of rare earth element Eu 3+ doping on the structural, dielectric, optical, and luminescence properties of synthesized materials. The analysis showed that the substitution of Bi 3+ cations with Eu 3+ leads to dielectric permittivity decreasing due to the structural distortion for the Eu-concentrated compositions and low polarizability of Eu 3+ . The band gap values predicted by electronic band structure calculation using DFT-HSE03 are in line with the experimental ones and tended to increase with the decrease in the unit cell parameters with Eu concentration changing. By the optical and luminescence measurements, the specific roles of Li- and Na-containing host types, additional phases, and dopant concentration in bismuth niobate pyrochlores are shown concerning the dielectric, structural, and Eu 3+ emission properties. All Eu-doped bismuth-based pyrochlore ceramics behave as high-frequency dielectrics up to 200 °C and have mixed conductivity (electronic, proton, and oxygen) at T > 200 °C. The obtained dielectric parameters make them suitable for high-frequency ceramic capacitors. |
