Anomalous transport in ferromagnetic GaAs/InxGa1-xAs/GaAs quantum well delta-doped with Mn and C

Transport, magnetotransport and magnetic properties of structures with GaAs/In_0.17Ga_0.83As/GaAs quantum well (QW) in GaAs have been measured in the temperature interval 4.2<T<300 K. The structures were delta-doped by Mn and carbon to provide magnetic properties and enhanced p-type conductivity. The ferromagnetic phase up to 400 K was detected by SQUID magnetometer. Anomalous Hall-effect and negative magnetoresistance was observed at low temperatures. The calculations of temperature dependence of resistance have been carried out. The contributions of various hole scattering mechanisms are analyzed. The quantitative consistency of the calculated and measured temperature dependence of sheet resistance is found. The reasons for occurrence of negative magnetoresistance are explained quantitatively as the reduction of the spin-flip scattering by aligning spins by magnetic field.