Investigation of microstructures in a Fe/Al2O3/Fe tunneling junction prepared using the ion-beam sputtering technique

A series of Fe/Al2O3/Fe tunneling junction samples were fabricated using the ion beam sputtering technique. The microstructures of these samples were analyzed using X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and high resolution transmission electronic microscopy (HRTEM). The results show that Al2O3 layers are well formed in the sample, but that an interdiffusion exists mainly at the interface between the bottom Fe and Al2O3 layers.