A ballistic electron emission microscopy study of ferromagnetic thin films embedded inAu/GaAs(100)

Abstract

A ballistic electron emission microscopy facility has been used toinvestigate hot electron transport through Au/M/Au and Au/M thin films(M = Fe,Co) grown on GaAs(100) substrates. The hot electron attenuation through the Au/Fe/Autrilayer roughly exhibited an exponential relationship with Fe interlayer thickness. Twovalues of Fe thickness (0.4 and 0.85 nm) were used to compare the differences between Feembedded at the centre of the Au layer and Fe at the metal–semiconductor interface.For the thicker Fe layer, there is a large difference in terms of the transmittedballistic electrons between the two structures, with the ‘at-interface’ structureexhibiting substantially increased transmission. This difference was not foundin the Au/Co system with comparable Co thickness. The results suggest thatthe behaviour of transmitted hot electrons is dominated by the formation of thecontinuous metal layers with strong scattering at the metal–metal interfaces.