Magneto-optic effect of the ferromagnetic diluted magnetic semiconductor Ga1−xMnxAs

Abstract

Magnetic circular dichroism (MCD) of a ferromagnetic diluted magnetic semiconductor Ga1−xMnxAs films was measured to clarify their electronic structure. Strong enhancement of MCD by Mn substitution indicated a strong sp–d hybridization. The p–d exchange interaction was concluded to be antiferromagnetic, which was in contrast with the reported ferromagnetic p–d exchange in very diluted paramagnetic GaAs:Mn bulk crystals. The change of the character of the p–d exchange interaction is due to the unique feature of Ga1−xMnxAs that the relative abundance of the neutral and ionized Mn acceptors controls the p–d exchange.