Room temperature ferromagnetism in (In1-xNix)2O3 thin films

Polycrystalline (In1−xNix)2O3 thin films (x=0.00, 0.03, 0.05 and 0.07) were deposited on glass substrates by electron beam evaporation technique. The effect of Ni concentration on composition, structural and magnetic properties of (In1−xNix)2O3 thin films was studied. Increment in the Ni concentration does increase the oxygen vacancies and ferromagnetic strength in (In1−xNix)2O3 thin films. X-ray photoelectron spectroscopy (XPS) studies indicate the dopant Ni exists in Ni (II) state in In2O3 host. Ferromagnetism was attributed to intrinsic nature of the sample rather than any secondary magnetic phases exist in the films. The observed ferromagnetism in (In1−xNix)2O3 was attributed to ferromagnetic exchange interaction between Ni2+ ions via single free electron trapped in oxygen vacancy. Increase in oxygen vacancies with Ni concentration lead to increase in such an oxygen vacancy mediated ferromagnetic pairs resulting in increase in ferromagnetic strength with Ni concentration.