Keywords:Ferromagnetic semiconductors, p-n junctions, magnetoresistance
Ferromagnetic p-n junctions consist of n-(In0.84,Fe0.16)Sb (20 nm)/ GaSb (t = 0 – 4 nm)/ p-(Ga0.8,Fe0.2)Sb (40 nm) heterojunctions grown on p+-GaAs substrates by low-temperature molecular beam epitaxy. Magnetic properties investigated by magnetic circular dichroism spectroscopy indicate that the (In,Fe)Sb/(Ga,Fe)Sb samples have high TC (170 – 310 K). The typical (I – V) characteristics of the samples with a spacer thickness t = 2 and 4 nm at 3.7 K are non-linear and show the rectifying properties. Large positive MR (58%) was observed at 300 mV at 3.7 K for the sample with a thin spacer (t = 2 nm), which may be due to the spin-splitting in the band structure of (In,Fe)Sb and (Ga,Fe)Sb under magnetic field. A negative MR (–1.3%) caused by the spin valve effect was observed at 50 mV at 3.7 K for the sample with t = 4 nm, which results from the parallel-antiparallel magnetization switching of the (In,Fe)Sb and (Ga,Fe)Sb layers. Our results indicate that the transport properties of the (In,Fe)Sb/(Ga,Fe)Sb heterostructures strongly depend on the spacer thickness, and the (In,Fe)Sb/(Ga,Fe)Sb p-n junctions with large MR (58%) are very promising for spintronics devices
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