Fabricacion y caracterizacion de peliculas de oxido de zinc dopado con elementos magneticos.

摘要

Previous works had predicted that ZnO doped with 3d transition metals can exhibit ferromagnetism at room temperature, which can be used in spintronics applications. Based in this motivation we started preparing targets of Zn 0.95Co0.1O, Zn0.95Co0.05O and Zn 0.95Co0.05Al0.01O by solid state reaction. Using the targets, thin films were prepared by pulsed laser deposition (PLD) on a sapphire substrate (Al2O3) cut-c and cut-r. The structural analysis by X-ray Diffraction (XRD) shows high quality crystallization due to a growth in the c direction, perpendicular to the substrate. The XRD spectrum did not show Co in other phases, successfully obtaining the substitution of Zn atoms by Co and Al atoms. The films were fabricated with a uniform thickness under appropriate growth conditions. The electric characterization using Hall Effect confirmed the n-type nature of ZnO. The carrier's density decreased while the resistivity increases when the ZnO was doped with Co, contrary to what happens when ZnO was co-doped with Al and Co. The increase of thickness creates crystals with considerable dimensions. Despite the fact that the films had high structural quality and electrical properties, it did not show ferromagnetic behavior under the growing conditions used. The diamagnetic behavior of the substrate superimposes the weak ferromagnetic behavior of the films.