Influence of erbium doping on conduction behaviour of Y6-xSr4(SiO4)6F2 fluorapatite ceramic prepared by solution combustion method

Abstract

This paper reports the electrical conduction mechanism of Y6-xSr4(SiO4)6F2:xEr3+ (x = 1,1.25, 1.5, 1.75 mol%) fluorapatite ceramic prepared by solution combustion method. X-ray diffraction (XRD) analysis confirms the formation of hexagonal structure with crystallite size in the nano meter range. Scanning electron microscopy (SEM) images of prepared ceramic show elongated spheroid grains with higher grain connectivity. Frequency dependent dielectric studies in the frequency range from 10 Hz to 100 KHz were done. Dielectric constant of prepared ceramic with different doping concentration decreases with increase in frequency of applied a.c field. Dielectric loss follows the same trend along with dissipation of energy. Complex impedance spectroscopy is used as a tool to investigate the change in real part of impedance (Z′), imaginary part of impedance (Z″), and a.c conductivity (σ) with the applied frequencies. Drastic increase in impedance value is being governed by aggregations of grains which is confirmed by cole-cole plots showing dielectric response of prepared ceramics. A.C conductivity shows an enhancement towards upper range i.e. dispersive region with an increase in applied frequency by giving a view on the electrical conduction behaviour of the ceramic.