Dielectric properties of conventional and microwave sintered Lanthanum doped CaCu3Ti4O12 ceramics for high-frequency applications

Abstract

The colossal dielectric response of La-doped CaCu3Ti4O12 ceramics has been probed at room temperature for a frequency of 1Hz–20 MHz. In this work, the La-doped (CaCu3Ti4O12)x samples for x = 0.1, 0.2, and 0.3 have been sintered at 1100 °C using two different heating modes. SEM and EDS analysis investigated the microstructural chrysalis, grain size distribution, and the inhibitions of Cu-rich phase segregation into grain boundaries by the effect of La3+. The presence of main cubic single-phase of CCTO and the diminutive Bragg peak shift due to ion size effect of La3+ and Ca2+ have been identified by XRD for both conventional (CS) and microwave sintered (MWS) samples. XPS study revealed the effect of La3+ on the binding energies of Cu and Ti in CCTO. The dielectric properties namely dielectric constant (ϵ), tan δ, and dielectric relaxation peaks were measured using BDS in which CS and MWS La-doped samples demonstrated (ϵ) ∼ >104 and ∼ >103 along with low tan δ for x ≥ 0.1 at medium and high frequency (104–107Hz) than pure CCTO.