Structure and Dielectric Properties of Re0.02Sr0.97TiO3 (Re = La, Sm, Gd, Er) Ceramics for High-Voltage Capacitor Applications

• Published in: Journal of the American Ceramic Society 2013-08, Vol.96 (8), p.2551-2555
• Main Authors: Shen, Zong-Yang, Hu, Qi-Guo, Li, Yue-Ming, Wang, Zhu-Mei, Luo, Wen-Qin, Hong, Yan, Xie, Zhi-Xiang, Liao, Run-Hua
• Format: Article
• Language: English
• Subjects: Breakdown; Capacitors; Ceramics; Dielectric constant; Dielectrics; Erbium; Grain size; Rare earth metals; Strontium titanates
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/jace.12364

Rare–earth‐doped strontium titanate ceramics yielding the formula Re0.02Sr0.97TiO3 (Re–ST, Re = La, Sm, Gd, Er) were prepared by solid‐state reaction route. All Re–ST ceramics had single cubic perovskite structure similar to pure SrTiO3 (ST). The grain size of Re–ST ceramics dramatically decreased to 1–10 μm, depending on different rare‐earth elements, as compared to ~30 μm of pure ST. The relative dielectric constant of Re–ST ceramics (εr = 2750–4530 at 1 kHz) showed about 10–15 times higher than that of pure ST (εr = 300 at 1 kHz), whereas the dielectric loss of Re–ST ceramics still remained lower than 0.03 (at 1 kHz) at room temperature. Under 0–1.63 × 106 V/m bias electric field testing conditions, the εr of Re–ST ceramics at room temperature changed within 14%. The P–E results indicated that the Re–ST ceramics were linear dielectrics. Together with their relatively high breakdown strength (Eb > 1.4 × 107 V/m), the Re–ST ceramics could be very promising for high‐voltage capacitor applications. Meanwhile, the temperature stability of the εr of Re–ST ceramics was evaluated in a temperature range of −60°C–200°C.