Crystal structure and microwave dielectric properties of new alkaline earth vanadate A 4 V 2 O 9 (A = Ba, Sr, Ca, Mg and Zn) ceramics for LTCC applications

Abstract A 4 V 2 O 9 (A = Ba, Sr, Ca, Mg and Zn) ceramics have been prepared by conventional solid state ceramic route. The phase purity of the samples was confirmed by powder X-ray diffraction technique. Raman spectroscopic studies confirm the existence of (VO 4 ) 3− vibrational groups in A 4 V 2 O 9 ceramics. The possibility of existence of A 4 V 2 O 9 compositions in the AO-V 2 O 5 binary system was also ascertained. The dielectric constant and quality factor of the ceramics under study were carried out by Hakki and Coleman post resonator and cavity perturbation techniques respectively using a vector network analyzer. Among the A 4 V 2 O 9 compositions, Mg 4 V 2 O 9 ceramic exhibits good microwave dielectric properties such as low dielectric constant of 6.3, Qxf of 37,263 GHz and negative τ f of −43.5 ppm/ °C at an optimum sintering temperature of 940 °C. Powder X-ray diffraction and EDS analyses of the co-fired Mg 4 V 2 O 9 ceramic sample show excellent chemical compatibility with Ag electrode and hence can be used as a candidate material for LTCC applications.