Structural, morphological and electrical properties of new type Dy doped Ca6-xNa2Y2(SiO4)6(OH)2 hydroxyapatite compound synthesized by co – precipitation method

In this study Dy³⁺ doped Ca_6-xNa₂Y₂(SiO₄)₆(OH)₂ (x = 0 – 0.05 mol%) hydroxyapatite compound was synthesized by co – precipitation method. The structural analysis reveals that the prepared compound has single phase hexagonal structure with space group P6₃/m. Scanning electron microscopy images show that the grains have irregular morphology and the grain size lies between 120—800 nm. The dielectric and electrical conduction studies of hydroxyapatite compound was done over a wide range of frequency (10² – 10⁵ Hz) and temperature (50⁰C – 500⁰C) respectively. Dielectric measurement shows that orientational and space charge polarizations are the dominant polarization mechanisms. Complex impedance and electric modulus spectroscopy analysis shows that ionic conduction is the presiding conduction mechanism. Nyquist plots depict the contribution of grains rather than grain boundaries in the conduction phenomena. A.C conductivity analysis shows that hydroxyl (OH)⁻ and oxygen (O⁻²) ions were the main charge carriers responsible for conduction phenomena in hydroxyapatite compounds.