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Theses

Structures hybrides MnAs/GaAs : de la croissance aux propriétés de transport tunnel polarisé en spin

Abstract : In this thesis, the trail of the hybrid MnAs (ferromagnetic metal)/GaAs system was investigated in the context of spintronics with semiconductors. In order to realize MnAs/GaAs/MnAs heterostructures, we optimized the growth conditions of MnAs thin films on GaAs(111)B and that of utrathin layers of GaAs. We emphasized the absence of reactivity at MnAs/GaAs interfaces and deduced a tunnel barrier height of 0.7 eV. Magnetotransport measurements of MnAs/GaAs/MnAs junctions showed a strongly atypical bias dependence of the tunnel magnetoresistance. To interpret these new effects, we developed a spin-dependent resonant tunneling model though an inhomogeneous impurity distribution in the semiconductor. In agreement with predictions of the model, the control of the defects distribution inside the barrier led to significantly enhanced tunnel magnetoresistance effects and we deduced a high spin polarization at MnAs/GaAs interface.
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Theses
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https://tel.archives-ouvertes.fr/tel-00122726
Contributor : Vincent Garcia <>
Submitted on : Thursday, April 26, 2007 - 4:37:34 PM
Last modification on : Monday, November 16, 2020 - 2:44:03 PM
Long-term archiving on: : Thursday, September 23, 2010 - 4:19:19 PM

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  • HAL Id : tel-00122726, version 3

Citation

Vincent Garcia. Structures hybrides MnAs/GaAs : de la croissance aux propriétés de transport tunnel polarisé en spin. Matière Condensée [cond-mat]. Université Pierre et Marie Curie - Paris VI, 2006. Français. ⟨tel-00122726v3⟩

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