Magnetic-field effects in defect-controlled ferromagnetic Ga_{1-x}Mn_xAs semiconductors

摘要

We have studied the magnetic-field and concentration dependences of themagnetizations of the hole and Mn subsystems in diluted ferromagneticsemiconductor Ga_{1-x}Mn_xAs. A mean-field approximation to the hole-mediatedinteraction is used, in which the hole concentration p(x) is parametrized interms of a fitting (of the hole effective mass and hole/local moment coupling)to experimental data on the Tc critical temperature. The dependence of themagnetizations with x, for a given temperature, presents a sharply peakedstructure, with maxima increasing with applied magnetic field, which indicatesthat application to diluted-magnetic-semiconductor devices would requirequality-control of the Mn-doping composition. We also compare variousexperimental data for Tc(x) and p(x) on different Ga_{1-x}Mn_xAs samples andstress the need of further detailed experimental work to assure that theexperimental measurements are reproducible.