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Magnetismus Poster: Do., 13:00–15:30 D-P255
Transport properties of magnetic tunnel junctions with Co2MnSi electrode:
influence of temperature-dependent interface magnetization and electronic
band structure
Jan Schmalhorst 1 , Andy Thomas 1 , Sven Kämmerer 1 , Oliver Schebaum 1 ,
Marc D. Sacher 1 , Andreas Hütten 2 , Günter Reiss 1
1 Thin Films and Nano Structures, Department of Physics, Bielefeld University, 33501
Bielefeld, Germany – 2 Institute for Nano-Technology, Research Center Karlsruhe,
76021 Karlsruhe, Germany
The transport properties of Co2MnSi / AlOx / Co-Fe magnetic tunnel junctions showing
a tunnel magnetorestistance of 95 % at low temperatures are discussed with respect
to temperature dependent magnetic moments at the Co2MnSi / AlOx interface and
electronic band structure effects. These junctions show a considerably larger temperature
and bias voltage dependence of the tunneling magnetoresistance compared
to Co-Fe-B / AlOx / Co-Fe-B junctions, although the effective spin polarization of
Co2MnSi (66 %) is larger than Co-Fe-B (60 %). With increasing atomic disorder of the
interfacial Co2MnSi its magnetic moments decrease and show a stronger temperature
dependence. Even for the best achieved atomic ordering the corresponding spinwave
parameters of Mn and Co at the Co2MnSi / AlOx interface are significantly larger
than expected for Co2MnSi bulk and also larger than the spin wave parameters of Co
and Fe at a Co-Fe-B / AlOx interface. The influence of enhanced interfacial magnon
excitation in the Co2MnSi / AlOx / Co-Fe junctions on their transport properties will
be discussed.