Theoretical Investigation on Induced Magnetic Moment by Impurity Potential

Abstract

We have theoretically examined whether magnetic moment of 3d impurity such as Fe or Co can be induced or not in magnetic dilute alloy when atoms with high electronegativity such as halogen or oxygen ones are doped into nonmagnetic matrix. Based on the impurity Anderson model, we have analyzed the magnetic state in magnetic dilute alloys, considering that the effect of doping atoms can be regarded as the impurity potential. Using the mean field approximation, we evaluate the green function for d electrons. Through the self-consistent calculation with respect to the number of d electrons with spin ↑ or ↓, it is disclosed that, although the initial state is non-magnetic, a magnetic moment can be induced by an impurity potential caused by doping atoms. In particular, when doped atoms have large electronegativity and/or there exists a strong Coulomb repulsive interaction between conduction electrons and doped atoms, magnetic moment is found to be easily induced from non-magnetic state.