Magnetic moment of Mn in the ferromagnetic semiconductor (Ga0.98Mn0.02)As

Abstract

We have studied the quasibinary ferromagnetic semiconductor ${\mathrm{(Ga}}_{\mathrm{0.98}}{\mathrm{Mn}}_{\mathrm{0.02}}\mathrm{)As}$ by magnetic circular dichroism in x-ray absorption. We find a richly structured Mn absorption spectrum typical for localized $\text{3d}$ electrons. An analysis of the magnetization-averaged and dichroism line shapes shows a local Mn moment of ${\text{4.6μ}}_B,$ which is close to the Hund’s rule moment for the half-filled $\text{3d}$ shell. The magnitude of the dichroism reveals that only about 1/7 of the Mn atoms participate in the ferromagnetic order. Our experiment does not show a distinction between the ferro- and paramagnetic Mn atoms.