ELECTRONIC-STRUCTURE AND MAGNETISM OF HEXAGONAL IRON LAYERS

Using a tight-binding model, the recursion method and a self-consistent Stoner criterion to calculate the magnetic moments, we have investigated the magnetism of 6 hexagonal layers of Fe between ruthenium layers. In the ferromagnetic and antiferromagnetic states, we obtain a magnetic moment of about 2-mu-B per atom in the 4 inner iron layers and one dead magnetic iron layer at the interface. But in a ferrimagnetic state, a magnetic moment of 1.7-mu-B is obtained for the interface layer. Total energy has been computed and found lower than the paramagnetic state for all the three magnetic states. These are very close in energy, the most stable one being the antiferromagnetic state. To investigate the origin of the two dead layers, found experimentally, a study of the interface defects has been made, using a virtual crystal model.