Physical study of nano-structured MoO3 films codoped with cobalt and nickel in which there is a ferro-diamagnetic transition

Abstract

This work covers some physical investigations on (Co, Ni) codoped molybdenum oxide thin films deposited on glass substrates at 460 °C by the spray pyrolysis technique. The effects of Co and Ni contents on the structural, morphological, optical and magnetic properties of these films were studied using several physical investigations. First, X-ray diffraction analysis revealed the formation of an orthorhombic structure related to α-MoO3 allotropic phase with (020) and (040) preferred orientations. Also, the scanning electron microscopy (SEM) micrographs showed the enhancement of the surface roughness of MoO3 films by cobalt and nickel concentrations. Second, the optical investigations through reflectance and transmittance measurements indicated a direct transition of all prepared thin films with a remarkable increase of the optical band gap from 3.70 to 3.95 eV with increasing both Co and Ni elements. Finally, the magnetic measurements at room temperature revealed a ferromagnetic behavior of Co and Ni codoped MoO3 films. A ferro-diamagnetic transition phenomenon was occurred for codoped film at Ni 2%and Co 2%.