Preparation and properties of La and Nb co-doped TiO 2 colossal dielectric ceramic materials
- PDF / 7,659,743 Bytes
- 9 Pages / 595.276 x 790.866 pts Page_size
- 71 Downloads / 194 Views
Preparation and properties of La and Nb co‑doped TiO2 colossal dielectric ceramic materials X. W. Wang1 · Y. P. Zheng1 · B. K. Liang1 · G. Zhang1 · Y. C. Shi1 · B. H. Zhang1 · L. L. Xue1 · S. Y. Shang1 · J. Shang1 · S. Q. Yin1 · Y. C. Hu1 Received: 26 April 2020 / Accepted: 3 August 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract In this study, La + Nb co-doped T iO2 (LNTO; x = 0, 0.02, 0.05, 0.07) ceramics were prepared by the solid-state reaction method with high-purity TiO2, La2O3 and Nb2O5 powders. LNTO ceramics show dense microstructures with the second phase at the grain boundary, and La and Nb addition can inhibit the grain growth. Results of dielectric properties show that the dielectric constant of LNTO ceramics are enhanced largely (ε′ > 104) and that the dielectric loss is relatively low (tan δ ~ 0.1) compared with that of pure TiO2 (ε′ ~ 102) at low frequency. Within the test temperature range (30–500 °C) and test frequency range (0.5–1000 kHz), dielectric constants of LNTO ceramics display relatively high stability. The two peaks in modulus spectra could be explained by Maxwell–Wagner polarization. The results of dielectric and impedance spectra prove that the internal barrier layer capacitance model can be used to explain the colossal permittivity in (La + Nb) co-doped T iO2.
1 Introduction With the development of the microelectronics industry and digital technology, people have high-performance requirements for energy storage and conversion components, and thus the dielectric materials of capacitors play an important part. The study of the colossal permittivity (CP) of dielectric materials has become a hot spot in recent years [1, 2], including the systems of doped NiO [3], doped BaTiO3 [4–6], SrTiO3 [7], CaCu3Ti4O12 (CCTO) [8–10] and so on. The dielectric constant of BaTiO3 ceramics is higher than 5000, but it is not stable and the high dielectric constant can be obtained only in a small temperature range around the phase transition temperature [4]. The systems of doped NiO, SrTiO3 and C aCu3Ti4O12 (CCTO) can improve the dielectric stability of the samples, but their dielectric loss is relatively high, resulting in a relatively large energy loss in practical application [3–10]. Therefore, it is necessary
Y. P. Zheng, B. K. Liang, and G. Zhang have contributed equally to this work. * X. W. Wang [email protected] 1
Laboratory of Functional Materials, School of Physics, Henan Normal University, and Henan Key Laboratory of Photovoltaic Materials, Xinxiang 453007, China
to develop colossal permittivity materials to realize their practical applications. Recently, an article reported the excellent dielectric properties of In + Nb co-doped T iO2 ceramics [2]. It shows colossal permittivity (ε′ > 104) with low dielectric loss (tan δ ≤ 0.05) within the frequency range of 20 Hz–2 MHz and the temperature range of 80–450 K [2]. Therefore, researchers studied many kinds of ( A3+0.5, B5+0.5)xTi1−xO2 ceramics by changing the element, such as Y + Nb c
Data Loading...
