Dielectric and photoluminesent properties of (Ca2Mg3-xPbx)A2(Ti0.75Zr0.25)O12 [x = 0 & 0.25; A = Nb & Ta] microwave ceramics

Abstract

(Ca2Mg3−xPbx)A2(Ti0.75Zr0.25)O12 [x = 0 & 0.25; A = Nb & Ta] ceramics are prepared through the conventional solid-state route. The substitution of Zr decreases the calcination and sintering temperatures of pure (Ca2Mg3)(Nb/Ta)2TiO12. The structure of the samples is analyzed using X-ray diffraction method. The dielectric properties such as dielectric constant (er), quality factor (Qu x f) and temperature coefficient of resonant frequency (τf) are measured in the microwave frequency region. By Pb substitution in (Ca2Mg3)(Nb/Ta)2(Ti0.75Zr0.25)O12, thermal stability is achieved with the increase in dielectric constant and quality factor. The dielectric behavior at low frequency range 50 Hz–5 MHz is also studied. The microstructure of the sintered pellet is studied using scanning electron microscopy. The materials have intense emission lines in the wavelength region 590 nm to 750 nm. The compositions have good microwave dielectric properties and photoluminescence and hence are suitable for dielectric resonator and ceramic laser applications.