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Magneto‐transport properties of NiMnSb thin films on InSb single crystals: Negative giant magnetoresistance
Author(s) -
Gardelis S.,
Androulakis J.,
Viskadourakis Z.,
Papadopoulou E. L.,
Giapintzakis J.,
Rai S.,
Lodha G. S.,
Roy S. B.
Publication year - 2007
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.200673003
Subject(s) - magnetoresistance , condensed matter physics , materials science , giant magnetoresistance , pulsed laser deposition , thin film , magnetic field , ohmic contact , scattering , crystallite , film plane , layer (electronics) , magnetization , magnetic anisotropy , optics , nanotechnology , physics , metallurgy , quantum mechanics
In this study we investigated the magneto‐transport properties of the ohmic contact between polycrystalline NiMnSb thin films grown by pulsed laser deposition and n‐type degenerate InSb (100) substrates. An unusual negative giant magnetoresistance (n‐GMR) effect is found when the external magnetic field is parallel to the in‐plane current direction. A similar effect is also observed when Ni films are deposited on InSb substrates. On the other hand, no n‐GMR effect is displayed when the deposited film is nonmagnetic. Grazing‐incidence X‐ray reflectometry shows the formation of a low‐density NiMnSb layer at the interface. The presence of such a layer coincides with the appearance of the n‐GMR.We argue that the n‐GMR effect is due to magnetic precipitates formed at the interface during the growth of the magnetic films. We propose that these precipitates align their magnetic moments in the direction of the external magnetic field and thus, the spin dependent scattering of the electrons is reduced. The effect of these precipitates on the magnetoresistance depends on the thermal processing of the system. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)