Colossal permittivity of (Tm plus Nb) co-doped rutile-TiO2 ceramics with ultralow dielectric loss and excellent thermal stability

(Tm0.5Nb0.5)(x)Ti1-xO2 (x = 0, 0.01, 0.02, 0.04 and 0.06) (TNTO) ceramics were prepared by solid-state reaction method. The effect of (Tm+Nb) co-doping concentration on the phase, microstructure and dielectric properties of the fabricated ceramics were investigated. A ultralow dielectric loss (0.006, at 1 kHz) and colossal permittivity (CP) (2.17 x10(4), at 1 kHz) were obtained in the prepared TNTO ceramics (x = 0.01). The dielectric properties of the (Tm0.5Nb0.5)(0.01)Ti0.99O2 ceramics show excellent temperature- and frequencystability in the range of - 150-260 degrees C (Delta epsilon' (T)/epsilon' (30) < +/- 15%, at 1 kHz) and 20-10(6) Hz. It was found that, the dielectric properties of (Tm+Nb) co-doped TiO2 ceramics have three significant temperature-dependent relaxations caused by electron-pinned defect-dipoles (EPDD) effect, internal barrier layer capacitance (IBLC) effect and electrode effect, respectively. The reported (Tm+Nb) co-doped TiO2 ceramics with ultralow dielectric loss and excellent thermal stability could be considered as one of the most promising candidates for applications in microelectronics. (C) 2022 Elsevier B.V. All rights reserved.