Occurrence of Local Magnetic Moments in Disordered Materials

Abstract

There is a growing interest in magnetism in dilute magnetic systems and in amorphous materials due to new experimental results. The possibility of amorphous magnetic materials was first point out by Gubanov(1) over a decade ago and the existence of such materials has been confirmed(2) (3) . Dilute magnetic systems were studied both experimentally by alloying a ferromagnet with a non magnetic material and theoretically by using a Heisenberg model where the spins occupy only part of the lattice sites. In the following, we are interested not in the appearance of an ordered magnetic phase, assuming that moments exist on the sites, but on the appearance of these local magnetic moments in these disordered structures. Thus, we start from a band scheme, and introducing correlations between electrons, study the appearance of magnetism.