Diode Heterostructures with a Ferromagnetic (Ga,Mn)As Layer

Diode p-(GaMn)As/n-InGaAs/n(+)-GaAs heterostructures with different thicknesses (from 5 to 50 nm) of the (Ga,Mn)As dilute magnetic semiconductor layer have been fabricated and studied. The negative magnetoresistance effect reaching 6-8% is observed in a magnetic field of 3600 Oe; this effect is retained up to temperatures of 70-80 K and related to a decrease in the charge carrier scattering due to ferromagnetic ordering in the (Ga,Mn)As layer. The dependence of the magnetoresistance on the forward bias voltage is nonmonotonic, and the magnetoresistance maximum and the operating voltage rate are dependent on the (Ga,Mn)As layer thickness. The magnetic-field dependence of the magnetoresistance have a hysteresis shape determined by the influence of the tensile stresses in the (Ga,Mn)As layer grown above the relaxed InGaAs on the magnetization component perpendicular to the structure surface.