Veselinović Ljiljana, Mitrić Miodrag, Mančić Lidija, Jardim Paula M, Škapin Srečo Davor, Cvjetićanin Nikola, Milović Miloš D, Marković Smilja
Institute of Technical Sciences of SASA, Knez Mihailova 35/IV, 11000 Belgrade, Serbia.
The Vinča Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia.
Materials (Basel). 2022 Nov 29;15(23):8500. doi: 10.3390/ma15238500.
This paper reports a detailed study of crystal structure and dielectric properties of ruthenium-substituted calcium-copper titanates (CaCuTiRuO, CCTRO). A series of three samples with different stoichiometry was prepared: CaCuTiRuO, = 0, 1 and 4, abbreviated as CCTO, CCT3RO and CCRO, respectively. A detailed structural analysis of CCTRO samples was done by the Rietveld refinement of XRPD data. The results show that, regardless of whether Ti or Ru ions are placed in crystallographic position in 'O (CaCuTiRuO) unit cell, the crystal structure remains cubic with Im3¯ symmetry. Slight increases in the unit cell parameters, cell volume and interatomic distances indicate that Ru ions with larger ionic radii (0.62 Å) than Ti (0.605 Å) are incorporated in the CaCuTiRuO crystal lattice. The structural investigations were confirmed using TEM, HRTEM and ADF/STEM analyses, including EDXS elemental mapping. The effect of Ru atoms share in CaCuTiRuO samples on their electrical properties was determined by impedance and dielectric measurements. Results of dielectric measurements indicate that one atom of ruthenium per CaCuTiRuO unit cell transforms dielectric CCTO into conductive CCT3RO while preserving cubic crystal structure. Our findings about CCTO and CCT3RO ceramics promote them as ideal tandem to overcome the problem of stress on dielectric-electrode interfaces in capacitors.
本文报道了钌取代的钙铜钛酸盐（CaCuTiRuO，CCTRO）的晶体结构和介电性能的详细研究。制备了一系列具有不同化学计量比的三个样品：CaCuTiRuO， = 0、1和4，分别简称为CCTO、CCT3RO和CCRO。通过对XRPD数据进行Rietveld精修，对CCTRO样品进行了详细的结构分析。结果表明，无论Ti或Ru离子是处于'O（CaCuTiRuO）晶胞中的 晶体学位置，晶体结构均保持具有Im3¯对称性的立方结构。晶胞参数、晶胞体积和原子间距离略有增加，表明离子半径较大（0.62 Å）的Ru离子比Ti（0.605 Å）掺入了CaCuTiRuO晶格中。使用TEM、HRTEM和ADF/STEM分析（包括EDXS元素映射）对结构研究进行了确认。通过阻抗和介电测量确定了CaCuTiRuO样品中Ru原子的占有率对其电学性能的影响。介电测量结果表明，每个CaCuTiRuO晶胞中有一个钌原子会将介电的CCTO转变为导电的CCT3RO，同时保持立方晶体结构。我们关于CCTO和CCT3RO陶瓷的研究结果表明，它们是克服电容器中介电-电极界面应力问题的理想串联材料。
