Tunneling magnetoresistance in GaMnAs/AlAs/InGaAs/AlAs/GaMnAs double-barrier magnetic tunnel junctions

摘要

We have studied the tunneling magnetoresistance (TMR) of Ga_(0.94)Mn_(0.06)As/AlAs(d nm)/ In_(0.4)Ga_(0.6)As(0.42 nm)/AlAs(d nm)/Ga_(0.94)Mn_(0.06)As double-barrier magnetic tunnel junctions with various AlAs thicknesses (d=0.8-2.7 nm) grown on p+GaAs (001) substrates by low-temperature molecular-beam epitaxy. In some junctions, unusual inverse TMR, in which the tunnel resistance in antiparallel magnetization is lower than that in parallel magnetization, was observed. The TMR ratio oscillated between positive and negative values with increasing the AlAs thickness, suggesting the existence of the resonant tunneling effect in the InGaAs quantum well.