Colossal permittivity and high insulation resistivity in Dy- modified SrTiO3 lead-free ceramic materials with low dielectric loss

Abstract

High performance colossal permittivity (CP) ceramic materials are indispensable for the development of electronic devices. In this work, excellent Sr1-xDyxTiO3 (0.000 ≤ x ≤ 0.018) ceramic samples were prepared through a traditional solid phase method. It can be found that the insulation resistivity of 4.7 × 107 Ω/cm3 (DC 100V), the CP of 26712 and the low dielectric loss of 0.0065 (1 kHz) are obtained in x = 0.008 ceramic samples sintered in N2. Based on the analysis of XRD, XPS and comparison of sintering in different atmospheres, the excellent dielectric property is mainly determined by defect dipoles associated with oxygen vacancy (eg.TiTi'−VO⋅⋅−TiTi'). These defect dipoles limit the long-range transition of electrons and result in electronic pinning effect. Additionally, it can be perceived that the insulation resistivity of 1.12 × 109 Ω/cm3 (DC 100 V), the CP of 23134 and the low dielectric loss of 0.0098 (1 kHz) are achieved in x = 0.008 ceramic samples after reoxidation. According to the analysis of complex impedance spectroscopy, the improvement of the insulation resistivity of x = 0.008 ceramic samples is mainly attributed to the increase of the grain boundary resistance.