Phase-microstructure evolution and microwave dielectric characteristic of (1-x)(Sr0.5Ce0.5)TiO3+δ-xNdAlO3 solid solution

A perovskite solid solution (1-x)(Sr0.5Ce0.5)TiO3+delta-xNdAlO(3), x = 0.1 to 0.4 was prepared by conventional solid state method. X-ray diffraction spectra revealed a single phase with tetragonal structure, indicating that doping of NdAlO3 significantly stabilized the perovskite-like structure. The addition of NdAlO3 facilitated the formation of large plate-like grains with porous microstructure. The dielectric constant (epsilon(r)) decreased with increasing x because of the small ionic polarizability of NdAlO3. The Qxf value was strongly dependent on the microstructure of these ceramics. The temperature coefficient of resonant frequency (tau(f)) gradually shifted to near zero with a rise of x, which resulted from the decrease in tolerance factor (t). The solid solution with x = 0.4 sintered at 1550 degrees C for 4h showed a good combination of dielectric properties: epsilon(r) = 72, Qxf = 12052 GHz and tau(f) = +5 pmm/degrees C. (C) 2017 Elsevier Ltd. All rights reserved.