Synthesis, characterization, and dielectric properties of low loss LaBO3 ceramics

The preparation, sintering behaviour, and dielectric properties of low loss LaBO3 ceramics have been investigated. Single-phase LaBO3 powder was synthesized by the conventional solid-state ceramics route and dense ceramics (relative density >96%) with uniform microstructure (grain size similar to 30 mu m) were obtained by sintering at 1300 degrees C in air. The electrical conductivity of LaBO3 follows the Arrhenius law and the related activation energies for electrical conduction of bulk and grain boundary are 0.62 eV and 0.90 eV, respectively. The LaBO3 ceramics sintered at 1300 degrees C exhibit excellent microwave dielectric properties with a relative permittivity, epsilon(r) similar to 11.8, a quality factor, Q x f(0) value similar to 76,869 GHz (at similar to 15 GHz), and a negative temperature coefficient of resonant frequency tau(f) similar to -52 ppm/degrees C. (C) 2013 Elsevier Ltd. All rights reserved.