Diode heterostructures with narrow-gap ferromagnetic A$^{3}$FeB$^{5}$ semiconductors of various conduction type

Diode structures with ferromagnetic narrow-gap semiconductors A$^{3}$FeB$^{5}$ as only $p$-region ($p$-GaFeSb/$n$-InGaAs), only $n$-region ($n$-InFeSb/$p$-InGaAs), $p$- and $n$-regions ($p$-GaFeSb/$n$-InFeSb, $p$-GaFeSb/$n$-InFeAs) for $p$–$n$ junction were fabricated by pulsed laser deposition in vacuum. The composition of ferromagnetic semiconductor layers and their thicknesses, determined by X-ray photoelectron spectroscopy, generally correspond to the technological data for diode structures. In particular, the thickness of the GaFeSb layer is 25–30 nm, and the thickness of the InFeAs and InFeSb layers is 35–40 nm. The iron content in InFeSb ranges from 25 to 35 at.%. The GaFeSb layer contains from 15 to 41 iron at.%, and the InFeAs layer – 35 iron at.%. The chemical analysis of the structures revealed the presence of chemical bonds Fe-As (Sb), In-Fe and Fe-Ga. Therefore, it can be assumed that Fe atoms in the fabricated structures can substitute for elements of groups III and V simultaneously. All structures exhibit the effect of negative magnetoresistance at sufficiently low observation voltages of the effect (up to 50 mV), in low magnetic fields (up to 3600 Oe), and at high measurement temperatures. For GaFeSb/InFeSb, GaFeSb/InFeAs diodes, negative magnetoresistance was first observed at room temperature. The hysteresis form of the dependences of the resistance on the magnetic field suggests the effect of the ferromagnetic properties of the layers of narrow-gap semiconductors on the transport of carriers in the structures.