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Structure, ferromagnetism and magnetotransport of epitaxial (Ga,Mn)As/GaAs structures
Author(s) -
Brunner K.,
Gould C.,
Schmidt G.,
Molenkamp L. W.
Publication year - 2006
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.200622382
Subject(s) - condensed matter physics , ferromagnetism , spintronics , curie temperature , materials science , magnetoresistance , molecular beam epitaxy , heterojunction , quantum tunnelling , magnetization , magnetic semiconductor , epitaxy , nanotechnology , physics , magnetic field , layer (electronics) , quantum mechanics
In this review, we describe the structural, magnetic and magnetotransport properties of one of the most advanced ferromagnetic semiconductor material systems, (Ga,Mn)As/GaAs heterostructures and nanostructures. Molecular beam epitaxy at low substrate temperature is applied to deposit epitaxial layers without MnAs cluster formation but with homogeneous incorporation of substitutional Mn up to about 8% content and with concomitant hole carrier densities in the 10 21 cm –3 range. Epitaxial strain, Mn content, p‐doping and defects that are related to low‐temperature growth may strongly influence the ferromagnetic properties, like Curie temperature, remanent magnetization and magnetic anisotropy. This is well understood within the Zener model for ferromagnetic ordering of Mn ions that is mediated by p–d exchange interaction with free holes in the complex, anisotropic valence band states. The interplay of ferromagnetism and electronic band structure manifests in the various magnetotransport phenomena, like anomalous Hall effect and spin valve tunneling transport. In particular, tunneling structures reveal many novel features, such as the tunneling anisotropic magnetoresistance (TAMR), that highlight the interplay of magnetic and electronic properties and may be pathways to future spintronics devices. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)