Interfacial, electrical, and spin-injection properties of epitaxial Co{sub 2}MnGa grown on GaAs(100)

Journal Article · Mon Jun 15 00:00:00 EDT 2009 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3148298· OSTI ID:21352267

Damsgaard, C D ^[1]; Hickey, M C ^[2]; Holmes, S N ^[3]; Feidenhans'l, R; Mariager, S O ^[4]; Jacobsen, C S; Hansen, J B ^[1]

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1. Department of Physics, Technical University of Denmark, DK-2800, Lyngby (Denmark)
2. Department of Physics, Cavendish Laboratory, University of Cambridge, J. J. Thomson Avenue, Cambridge, CB3 0HE (United Kingdom)
3. Cambridge Research Laboratory, Toshiba Research Europe Limited, 208 Cambridge Science Park, Milton Road, Cambridge, CB4 0GZ (United Kingdom)
4. Niels Bohr Institute, Nano-Science Center, University of Copenhagen, 2100 Copenhagen O (Denmark)

The interfacial, electrical, and magnetic properties of the Heusler alloy Co{sub 2}MnGa grown epitaxially on GaAs(100) are presented with an emphasis on the use of this metal-semiconductor combination for a device that operates on the principles of spin-injection between the two materials. Through systematic growth optimization the stoichiometry in the bulk Co{sub 2}MnGa can be controlled to better than +-2%, although the interface is disordered and limits the spin-injection efficiency in a practical spintronic device irrespective of the half-metallic nature of the bulk metal. Molecular beam epitaxial growth was monitored in situ by reflection high energy electron diffraction and the bulk composition was measured ex situ with inductively coupled plasma optical emission spectroscopy. The Co{sub 2}MnGa L2{sub 1} cubic structure is strained below a thickness of 20 nm on GaAs(100) but relaxed in films thicker than 20 nm. Electrical measurements on the Co{sub 2}MnGa reveal general characteristics of a disordered electron system with insulating behavior for layer thicknesses <4 nm. Thicker layers show a negative magnetoresistance with extraordinary Hall effect constants up to 30 OMEGA T{sup -1}. Spin polarization transfer across the interface between Co{sub 2}MnGa and GaAs is approximately 6.4% at 5 K in the current of a GaAs p-i-n diode even with compositional disorder at the interface.

• OSTI ID: 21352267
• Journal Information: Journal of Applied Physics, Vol. 105, Issue 12; Other Information: DOI: 10.1063/1.3148298; (c) 2009 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
COBALT ALLOYS
CRYSTAL GROWTH
ELECTRON DIFFRACTION
EMISSION SPECTROSCOPY
GALLIUM ALLOYS
GALLIUM ARSENIDES
HALL EFFECT
HEUSLER ALLOYS
LAYERS
MAGNETIC PROPERTIES
MAGNETORESISTANCE
MOLECULAR BEAM EPITAXY
SEMICONDUCTOR MATERIALS
SPIN
SPIN ORIENTATION
STOICHIOMETRY
THIN FILMS
ALLOYS
ALUMINIUM ALLOYS
ANGULAR MOMENTUM
ARSENIC COMPOUNDS
ARSENIDES
COHERENT SCATTERING
COPPER ALLOYS
COPPER BASE ALLOYS
CORROSION RESISTANT ALLOYS
CRYSTAL GROWTH METHODS
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
EPITAXY
FILMS
GALLIUM COMPOUNDS
MANGANESE ALLOYS
MATERIALS
ORIENTATION
PARTICLE PROPERTIES
PHYSICAL PROPERTIES
PNICTIDES
SCATTERING
SPECTROSCOPY
TRANSITION ELEMENT ALLOYS