Studies on structural and electrical properties of Mg0. 5+y (Zr2-yFey) 2 (PO4) 3 ceramic electrolytes

The sample of Mg0. 5+y (Zr1-yFey) (2) (PO4) (3) (0.0 <= y <= 0.5) was synthesized using the sol-gel method. The structures of the samples were investigated using X-ray diffraction and Fourier transform infrared spectroscopy measurement. XRD studies showed that samples had a monoclinic structure which was iso-structured with the parent compound, Mg0.5Zr (PO4) (3). The complex impedance spectroscopy was carried out in the frequency range 1-6MHz and temperature range 303 to 773 K to study the electrical properties of the electrolytes. The substitutions of Fe3+ with Zr4+ in the Mg0.5Zr (PO4) (3) structure was introduced as an extrainterstitial Mg2+ ion in the modified structured. The compound of Mg0. 5+y (Zr1-yFey) (2) (PO4) (3) with y = 0.4 gives a maximum conductivity value of 1.25 x 10(-5) S cm(-1) at room temperature and 7.18x 10(-5) S cm(-1) at 773 K. Charge carrier concentration, mobile ion concentration, and ion hopping rate are calculated by fitting the conductance spectra to power law variation, sigma(ac) (omega) = sigma(o) + A omega(alpha). The charge carrier concentration and mobile ion concentration increases with increase of Fe3+ inclusion. This implies the increase in conductivity of the compounds was due to extra interstitial Mg2+ ions.