The role of Cu codoping on the Fe metal clustering and ferromagnetism in Fe-doped In2O3 films

We have grown room temperature ferromagnetic Fe, and Fe,Cu-codoped In2O3 films on sapphire substrates by pulsed laser deposition. The magnetization of the Fe-doped In2O3 films was independent of the thickness and the observed ferromagnetism was almost homogeneous. The addition of Cu caused the films to exhibit obvious thickness dependent magnetization and the ferromagnetism became inhomogeneous. The temperature dependence of the magnetization, X-ray absorption fine structure and magnetic circular dichroism data, clearly established the presence of Fe metal clusters in Fe,Cu-codoped In2O3 films, which contribute to the inhomogeneous ferromagnetism.