Synthesis and dielectric characterization of pure and cobalt doped palmierite [K2Pb(SO4)2] mineral

Palmierite minerals were found in Mt.Vesuvius, Italy. It is a rare sulfate mineral. During the past, only the crystal structure of palmierite mineral was dealt with. In the present work, palmierite was synthesized by co-precipitation route and doped with cobalt at different molar concentrations. Powder x-Ray Diffraction studies were carried out to understand the crystalline nature and lattice distortion of the as-synthesized pure and doped samples. The materials were subjected to FTIR and Raman analysis to identify the functional groups present in it. The morphological studies were carried out. The room temperature PL spectra shows dominant emission peaks at 360 nm, 521 nm and 595 nm. The cobalt doped samples has high dielectric constant value of 12128 while the pure palmierite has the value of 10375 but both the samples have very low loss factor of 0.5 at low frequency region. The loss factor also shifted towards low frequency region on doping. The dielectric behaviour of palmierite has interesting outcome upon doping and the results were discussed.