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Proceedings Paper

Gate-tunable large magnetoresistance in semiconductor-based spin valve devices (Conference Presentation)
Author(s): Mariusz Ciorga; Martin Oltscher; Franz Eberle; Thomas Kuczmik; Andreas Bayer; Dieter Schuh; Dominique Bougeard; Dieter Weiss

Paper Abstract

A spin-dependent and electric-field tunable magnetoresistance (MR) of a semiconducting (SC) channel placed between two ferromagnetic (FM) contacts is a key ingredient in many novel spin-based device concepts. Whereas successful realization of such devices requires a large magnetoresistance signal, the signals measured in semiconductor-based devices are usually very low, well below 1\%, because of highly resistive tunnel FM/SC interfaces. In this talk, we will discuss how the finite electric fields effects in lateral FM/SC/FM devices lead to enhancement of the measured magnetoresistance by increasing the efficiency of the spin transport in the channel and boosting spin-to-charge conversion at the FM/SC interface. We will illustrate this discussion with the results of our recent experiments on lateral all-semiconductor spin valve devices with a transport channel formed in the two-dimensional electron system embedded in GaAs/(Al,Ga)As interface and with ferromagnetic (Ga,Mn)As/GaAs Esaki diodes as source and drain contacts [1]. We have measured very large two-terminal spin valve signals, in order of 1 kOhm in such devices, with MR reaching even up to 80\% in the nonlinear regime of the current-voltage characteristic [2]. We will also demonstrate that the MR signal can be additionally tuned by means of an electric gate, with the gating scheme based on switching between uni- and bidirectional spin diffusion, without resorting to spin–orbit coupling. The work has been supported by Deutsche Forschungsgemeinschaft (DFG) through SFB689. [1] M. Oltscher et al., Phys. Rev. Lett. 113, 236602 (2014) [2] M. Oltscher et al., Nature Commun. 8, 1807 (2017)

Paper Details

Date Published: 18 September 2018
Proc. SPIE 10732, Spintronics XI, 107320J (18 September 2018); doi: 10.1117/12.2319375
Show Author Affiliations
Mariusz Ciorga, Univ. Regensburg (Germany)
Martin Oltscher, Univ. Regensburg (Germany)
Franz Eberle, Univ. Regensburg (Germany)
Thomas Kuczmik, Univ. Regensburg (Germany)
Andreas Bayer, Univ. Regensburg (Germany)
Dieter Schuh, Univ. Regensburg (Germany)
Dominique Bougeard, Univ. Regensburg (Germany)
Dieter Weiss, Univ. Regensburg (Germany)

Published in SPIE Proceedings Vol. 10732:
Spintronics XI
Henri-Jean Drouhin; Jean-Eric Wegrowe; Manijeh Razeghi; Henri Jaffrès, Editor(s)

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