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

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 (?), tan δ, and dielectric relaxation peaks were measured using BDS in which CS and MWS La-doped samples demonstrated (?) ～ >10⁴ and ～ >10³ along with low tan δ for x ≥ 0.1 at medium and high frequency (10⁴–10⁷Hz) than pure CCTO.