Magnetic properties of Er and Er, O-doped GaAs grown by organometallic vapor phase epitaxy

Magnetic and magneto-transport behaviors in GaAs : Er and GaAs : Er, O films which showed strong luminescence at around View the MathML source due to intra-4f shell transitions of Er3+ were investigated. Even at 2K, the magnetizations at 5T of the GaAs : Er and GaAs : Er, O films were about 0.6%, much less than that calculated using effective moment of Er3+ ion. Although the PL intensity was strongly related to the coordination around Er, the magnetization properties were independent of those atom configurations. Moreover, the positive magneto-resistance (MR) of 12% was observed at 300K in the GaAs : Er, O film with low carrier density. The change in MR ratio increased in proportion to the square of applied magnetic field and may be explained by the typical positive MR mechanism for hopping effect by band shrinkage induced by impurity doping in semi-insulator semiconductor. Effects of Zn doping on the magnetization and magneto-transport behavior were also discussed.