Ethylene glycol/citric acid stabilized wet chemically synthesized Y 2 CoNiO 6 , and its structural, dielectric, magnetic and electrochemical behavior

We report the synthesis of the novel double perovskite Y 2 CoNiO 6 by an ethylene glycol and citric acid stabilized facile wet sol–gel chemical process. The material is iso-structural to the yttrium oxide cubic phase of Ia3 symmetry ( a = 10.5957 Å). The Raman vibrational modes at the wave numbers of 247, 489, 518, 566, 604, 649, 741 and 824 cm −1 further confirmed the formation of Y 2 CoNiO 6 . The Y 2 CoNiO 6 shows the room temperature dielectric constant of 5660 at the frequency of 500 Hz which increases further with the increase of temperature. It exhibits a predominant paramagnetic behavior with a second-order phase transition from antiferromagnetic to paramagnetic at the Néel temperature being T FC = 51.65 K. The energy density of 19.97 W h kg −1 at 1 A g −1 and power density of 1324 W kg −1 at 6 A g −1 have been obtained. The effective charge storage is due to redox reaction of Co 2+ /Co 3+ and Co 3+ /Co 4+ as supported by X-ray photoelectron spectroscopy. The capacitance retainability of 98.5