Structural, dielectric and magnetic properties of double perovskite-La2CoNiO6 ceramics synthesised by wet chemical route

Abstract

The polycrystalline double perovskite-La2CoNiO6 ceramics were successfully synthesised by facile wet chemical route. The X-ray diffraction pattern has confirmed the formation of rhombohedral phase with R3c symmetry and calculated value of lattice parameters as, a = b = 5.64 A and c =13.25 A, respectively. The presence of La3+ ions, Co2+/Co3+ ions, and Ni2+ ions on the surface of La2CoNiO6 has been exhibited via X-ray photoelectron spectroscopy. The temperature and frequency dependent dielectric and impedance analysis has revealed the effect of grains and grain boundaries in the relaxation process. The observed values of ac conductivity varied from 5.27 × 10−6 S/m to 1.06 × 10−5 S/m with variation of temperature from 300 K to 473 K at frequency of 1 kHz. Further, La2CoNiO6 is a new ferromagnetic semiconductor exhibiting spin glass transition at low temperature of ~50 K. The present first report on structural, dielectric and magnetic study makes La2CoNiO6 a promising material for electronic devices applications.