Dielectric properties of Nb-doped CaCu 3Ti 4O 12 electroceramics measured at high frequencies

Abstract

In this work, Nb dopant was introduced into CaCu 3Ti 4O 12 (CCTO) electroceramic in order to improve the dielectric properties. The CCTO electroceramic was prepared using the solid state reaction method. An X-ray diffractometer (XRD) analysis proved the formation of a single CCTO phase after sintering at 1040 °C for 10 h. Abnormal grain growth was observed in undoped CCTO and 1 mol% Nb-doped CCTO. Normal grain growth was produced at Nb dopant levels higher than 3 mol%. Dielectric properties were measured at a frequency range of 1 MHz to 1 GHz. It was found that CCTO doped with 1 mol% Nb gave the highest dielectric constant of 18,000 at 1 MHz. Meanwhile, the lowest dielectric loss (0.31) at 1 MHz was given by CCTO doped with 10 mol% Nb. The dielectric constant between 10 MHz and 1 GHz was almost stable with values at around 500.