Coercive field and magnetization deficit in Ga1−xMnxAs epilayers

Abstract

We have studied the field dependence of the magnetization in epilayers of the diluted magnetic semiconductor Ga1−xMnxAs for 0.0135<x<0.083. Measurements of the low temperature magnetization in fields up to 3 T show a significant deficit in the total moment below expected for full saturation of all the Mn spins. These results suggest that the spin state of the nonferromagnetic Mn spins is energetically well separated from the ferromagnetism of the bulk of the spins. We have also studied the coercive field (Hc) as a function of temperature and Mn concentration, finding that Hc decreases with increasing Mn concentration as predicted theoretically.