Vibrational studies and microwave dielectric properties of Ca3Te2Zn3O12 ceramic with garnet structure

Microwave dielectric properties of Ca3Te2Zn3O12 ceramic with garnet structure, synthesized via conventional solid-state ceramic route are studied for the first time. The X-ray diffraction pattern shows that the compound having a garnet structure, belongs to cubic symmetry with Ia-3d space group. Raman and infrared spectroscopic results are in good agreement with group theoretical predictions for the cubic symmetry. Valence states of ions present in Ca3Te2Zn3O12 ceramic are confirmed using X-ray photoelectron spectroscopy. The ceramic sintered at 1100 degrees C/4 h exhibited maximum densification of 94%, relative permittivity (epsilon r) of 10.9, a quality factor (Q(u) x f) of 20,340 GHz and a temperature coefficient of resonant frequency (tau f) of - 31 ppm/degrees C at a frequency of 12.6 GHz. The narrow A1g mode present in the Raman spectrum can be well correlated with the observed quality factor.