Structural tuning of dielectric properties of Ce-substituted Nd2Zr2O7

Abstract

Rare earth zirconates with pyrochlore type structure have shown a potential for practical applications due to their stable crystal structure with tunable lattice parameters. In this context, a series of Ce-substituted neodymium zirconates with general formula, Nd2Zr2−xCexO7 (x = 0.0, 0.4, 0.8, 1.2, 1.6, 2.0) was synthesized using wet chemical sol–gel auto-combustion technique. Structural analysis confirmed the formation of stable pyrochlore phase with space group Fd3m. The scanning electron microscopic analysis revealed that the parent compound adopted a mixed morphology (rectangular, spherical, squared etc.) with sharp grain boundaries and considerable porosity. A significant agglomeration was observed with Ce-substitution at Zr-site which improved the density of material. The stoichiometric composition of the elements present in the samples was confirmed by energy dispersive X-ray spectroscopy. The response of the material to external electric field of varying frequency was studied through impedance spectroscopy which confirmed the active contribution of grains and grain boundaries in the form of electrical response of the material. The nature of mobility of charge carriers was checked by the interaction of external varying electric field with the electric dipole moments of the material. This whole study provides valuable information about the energy storage capacity of the material and thus determines the potential of the material to be used in energy storage devices. Keywords: Ce-substituted Nd2Zr2O7, Structural tunability, Impedance spectroscopy, Energy