Preparation of the subnanometer thick epitaxial Al2O3(0001) layers on Fe(110) for magnetic tunnel junctions

Growth as well as crystallographic and electronic properties of thin AlOx layers on Fe(110) were studied by means of low-energy electron diffraction and Auger-electron spectroscopy. Al layers of different thickness were deposited on Fe(110) and successfully oxidized to AlOx. The step-by-step oxidation of thin Al layers at room temperature leads to the formation of amorphous AlOx on top of the Fe(110) surface. A subsequent annealing at 250 °C of the oxidized 7-Å thick Al layer results in the formation of a well-ordered Al2O3(0001) layer on the Fe(110) surface.