Estudo do efeito da dopagem da terra-rara európio na estrutura, morfologia e nas propriedades magnéticas da matriz semicondutora ZnO visando obter um Semicondutor Magnético Diluído (SMD)

Abstract

The search for the development of increasingly sophisticated semiconductor devices, with greater efficiency and processing speed, has induced the electronic industry to increase the number of components that compose it and seek to miniaturize them. However, limits have been found in relation to the quantity and size of these components. In this context, spintronic technology based on the control and manipulation of the electron spin emerges, making it possible to use the ability to process data and to store informations simultaneously, obtaining greater efficiency, higher data processing speed and lower energy consumption. This technology can be achieved by means of the Diluted Magnetic Semiconductors (DMS), with zinc oxide (ZnO) being a promising candidate for its production, since it exhibits ferromagnetic behavior above room temperature through the doping of transition metal ions or rare earths in its structure, such as the Europium (Eu), which has stood out due to the good magnetic moment (≈ 6,9 μB). In this work, a ZnO based DMS doped with Eu3+ ions at concentrations of 0.05 and 0.1 moles was synthesized by combustion reaction. The samples were sintered at 1100°C for 30 minutes. In order to evaluate the effect of europion concentration and sintering on the structure, band gap, magnetic properties and morphology of ZnO, the samples were analysed before and after sintering by X-ray Diffraction (XRD), Spectroscopy in the Ultraviolet and Visible region (Uv-Vis), Vibrant Sample Magnetomy (VSM) and Scanning Electron Microscopy (SEM). From the results obtained, it was found that there was formation of second phase (Eu2O3), with the exception of the sample in the condition of powder doped with 0.05 mols of europium. It was observed that all samples, before and after sintering, exhibited band gap values within the semiconductor range and ferromagnetism at room temperature. In addition, it was possible to visualize that the morphology of the samples is significantly altered with the increase of the europion concentration in the system.