Rapid laser reactive sintering synthesis of colossal dielectric CCTO ceramics

Calcium copper titanate (CCTO) ceramics were successfully synthesized using a rapid laser reactive sintering method without conventional long heat treatment times. The microstructure, dielectric properties, and impedance spectroscopy results for CCTO sintered at laser power rates of 25-85Wwere investigated in detail. The X-ray diffractometry results showed that prepared CCTO is polycrystalline in a cubic structure with high purity. Scanning electron microscopy showed that CCTO sintered at 85Whas a dense microstructure with an average grain size of 30 nm. The dielectric permittivity of CCTO ceramics increased with increasing laser power over the entire frequency range and achieved a value of almost 10⁵ in the low-frequency region. The dielectric permittivity maintained almost constant values from 10² Hz to 10⁷ Hz, with lower dielectric loss (~0.1) from 10³ Hz to 10⁶ Hz, demonstrating good frequency stability. The impedance spectroscopy study showed that grain and grain boundary resistance decreased with rising laser power based on two parallel Resistor-Capacitance (RC) equivalent circuits in series. The activation energies for the grain boundaries were calculated from the impedance using the slope of ln versus 1/T and were found to be in the range of 0.53-0.63 eV. CCTO synthesized by rapid laser reactive sintering is competitive for practical applications.