Andreas Wittmann et al 2004 J. Phys.: Condens. Matter 16 S5645 doi:10.1088/0953-8984/16/48/022
Andreas Wittmann1, Claas-Henrik Möller1, Oliver Kronenwerth1, Matthias Holz2,3 and Dirk Grundler1,4
Show affiliationsWe review our recent work on ferromagnet/semiconductor hybrid structures. In particular we focus on magnetotransport experiments performed on Co/InAs/Co hybrid structures fabricated on the cleaved edge of an InAs/InGaAs heterostructure. By modulation doping we inserted a high-mobility two-dimensional electron system (2DES) between the Co source and drain contacts which were separated by about 0.2 µm. This separation was smaller than the mean free path in the 2DES. Two additional metallic gate electrodes were integrated, thus forming a prototype spin field-effect transistor on a cleaved (110) surface of an InAs/InGaAs heterostructure. Intriguingly, we observe two characteristic magnetotransport signals at 4.2 K: (a) a hysteretic spin-valve-like signal and (b) a large positive magnetoresistance. We attribute the latter to the extraordinary magnetoresistance effect, i.e. the magnetic-field induced current redistribution between the Co contacts and the 2DES.
75.70.Cn Magnetic properties of interfaces (multilayers, superlattices, heterostructures)
73.40.Sx Metal-semiconductor-metal structures
75.75.+a Magnetic properties of nanostructures
85.75.Hh Spin polarized field effect transistors
75.47.-m Magnetotransport phenomena; materials for magnetotransport
Condensed matter: electrical, magnetic and optical
Issue 48 (8 December 2004)
Received 20 June 2004
Published 19 November 2004
Andreas Wittmann et al 2004 J. Phys.: Condens. Matter 16 S5645
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