Stable colossal permittivity and low loss in (In_(0.5)Nb_(0.5))_(0.005)Ti_(0.995)O_2+x mol% ZrTiO_4 composite ceramics under DC bias voltage

摘要

In this study, (In0.5Nb0.5)(0.005)Ti0.995O2+x mol% ZrTiO4 (INTO-xZT) (0x75) composite ceramics were fabricated using a conventional solid-state reaction method. The effects of ZrTiO4 phase on the microstructure, dielectric properties, and response to DC bias were investigated. XRD and SEM results indicated that the co-doped TiO2 and ZrTiO4 coexisted well. epsilon decreased with increasing ZrTiO4 content x. For the sample with x=20, epsilon=9940, tan=0.03, and temperature coefficient of permittivity (@ 1kHz) variation+/- 15% over the temperature range from -60 degrees C to 85 degrees C were obtained. The grain-boundary resistance (R-gb) increased by almost two orders of magnitude in contrast to that of the sample with x=0. Stable colossal permittivity and low loss under DC bias (500V/cm) were observed for the sample with x=20. These outstanding dielectric properties were attributed to the considerable improvement in R-gb and the smaller grain size of the composite ceramics with appropriate ZrTiO4 content.