Magnetic, optical, microscopic and electrical behavior of Ca2−xYxCo2O5 prepared by a molten flux method

Abstract

In this present study, we have reported the preparation of yttrium doped polycrystalline Ca2−xYxCo2O5 (x=0.0–1.0) material by a molten flux method and its various properties like electrical, optical, dielectric and magnetic behaviors. Characterization techniques have been adopted to confirm its physical nature and properties. X-ray diffraction results confirmed the crystal structure of prepared Ca2−xYxCo2O5 as orthorhombic and the scanning electron microscope pictured the presence of platelet-shaped particles with the dimensions of 150–300nm. It also reveals the state of higher concentration of yttrium (Y3+) controls the grain size of Ca2−xYxCo2O5 ceramics. Further, we find out that the higher concentration of yttrium (Y3+) increases the optical band gap due to the occurrence of metal–insulator transition and also the same in electrical resistivity from 0.2mΩcm to 0.5mΩcm, which is due to the replacement of holes by Y3+ ions. The result of dielectric studies proves that the conduction mechanism of yttrium doped calcium cobalt oxide is due to space charge polarization. The magnetic saturation behavior shows the decreasing area in the hysteresis curve while the Y3+ concentration is increased, which is due to the phase transition of ferromagnetic to paramagnetic.