ABSTRACT
The doping of oxide-based semiconductors with rare-earth ions may serve as an alternative to transition metal doping with the possibility of room-temperature ferromagnetism. Here, highly transparent thin films of ZnO doped with a rare-earth element, Gd, were prepared via a sol-gel-derived precursor. A series of Gd-doped ZnO films with different Gd concentrations (0 to 8 at.%) were deposited onto glass substrates. XRD analysis revealed that the FWHM of the diffraction peaks increased with the increase of Gd composition which may indicate that the Gd incorporation decreased the crystallinity. However no new peaks associated with the formation of secondary phases such as GdO and Gd metal clusters were detected. The MFM images were seen to be more pronounced with the incorporation of Gd ions where we could clearly observe the magnetic signals at room temperature especially for the samples with higher Gd doping of 4 and 8 at.% Gd. Evidently, the magnetic domain size exhibited a significant increase with the increase of Gd composition in contrast to the undoped sample.
