Koroleva Mariia S, Ishchenko Aleksey V, Vlasov Maxim I, Krasnov Aleksei G, Istomina Elena I, Shein Igor R, Weinstein Ilya A, Piir Irina V
Institute of Chemistry, Federal Research Center Komi Science Center, Ural Branch, Russian Academy of Sciences, Syktyvkar 167982, Russia.
Ural Federal University, NANOTECH Center, Ekaterinburg 620002, Russia.
Inorg Chem. 2022 Jun 20;61(24):9295-9307. doi: 10.1021/acs.inorgchem.2c01037. Epub 2022 Jun 3.
Eu-doped bismuth-based BiMgNbO ( = Li and Na) pyrochlores were synthesized by the organic-inorganic precursor combustion technique. The study examined the effect of rare earth element Eu doping on the structural, dielectric, optical, and luminescence properties of synthesized materials. The analysis showed that the substitution of Bi cations with Eu leads to dielectric permittivity decreasing due to the structural distortion for the Eu-concentrated compositions and low polarizability of Eu. 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 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 > 200 °C. The obtained dielectric parameters make them suitable for high-frequency ceramic capacitors.
采用有机-无机前驱体燃烧技术合成了掺铕铋基BiMgNbO（=Li和Na）烧绿石。该研究考察了稀土元素铕掺杂对合成材料的结构、介电、光学和发光性能的影响。分析表明，由于铕富集成分的结构畸变和铕的低极化率，用铕取代铋阳离子会导致介电常数降低。使用DFT-HSE03通过电子能带结构计算预测的带隙值与实验值一致，并且随着铕浓度变化导致晶胞参数减小而趋于增加。通过光学和发光测量，展示了含锂和钠的主体类型、额外相以及铌酸铋烧绿石中掺杂剂浓度在介电、结构和铕发射性能方面的具体作用。所有掺铕铋基烧绿石陶瓷在高达200°C时表现为高频电介质，在高于200°C时具有混合导电性（电子、质子和氧）。所获得的介电参数使其适用于高频陶瓷电容器。
