Synthesis,characterization, thermal and dielectric properties of pure and cadmium doped calcium hydrogen phosphate

The synthesis of pure and cadmium doped calcium hydrogen phosphate as single crystal has been accomplished by a room temperature solution growth technique viz., silica gel technique. Silica gel obtained from sodium metasilicate with a strongly acidic cation exchanger in the H-form, was used for crystal growth experiments. The nature of the grown material was established by powder X-ray diffraction (PXRD) studies, whereas from single crystal X-ray diffraction (SXRD) the crystal system comes out to be monoclinic. The stoichiometry of the grown composition was established by energy dispersive X-ray analysis (EDAX). Fourier transform infrared spectroscopic (FTIR) studies signifies the presence of phosphate (PO₄)²⁻ group and water of crystallization. Thermo gravimetrical analysis and investigations of dielectric properties were undertaken to study the thermal stability, dielectric constant and transition temperature of the grown material. Dielectric studies suggest that there is a shift in the value of transition temperature (T_c) thereby indicating relaxor behaviour of the material.