Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 15: Poster:ThinFilms(1-33),Transp.(34-49),ExchBias(50-56),
Spindynamics(57-70),Micro-nanostr.Mat.(71-82),
Particles/Clust.(83-88), Mag.Imag./Surface(89-96),
Spinelectronics(97-109), Theory/Micromag.(110-116),
Spinstruct/Phasetr.(117-128),Magn.Mat.(129-139),
Aniso.+Measuring(140-145), MolMag.(146-152),
MSMA(153-156)
MA 15.97: Poster
Dienstag, 27. März 2007, 15:00–19:00, Poster A
Transport properties of magnetic tunnel junctions with Co2MnSi electrode: influence of temperature-dependent interface magnetization and electronic band structure — •Jan Schmalhorst1, Andy Thomas1, Oliver Schebaum1, Daniel Ebke1, Marc Sacher1, Andreas Hütten1, Andrej Turchanin2, Armin Gölzhäuser2, Elke Arenholz3, and Günter Reiss1 — 1Thin Films and Nano Structures, Department of Physics, Bielefeld University, 33501 Bielefeld, Germany — 2Department of Physics, Bielefeld University, 33501 Bielefeld, Germany — 3Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
The investigation of the temperature-dependent magnetic and chemical properties of the Co2MnSi / Al-O interface in Co2MnSi / Al-O / Co-Fe MTJs showed, that with increasing degree of disorder, interfacial magnetic moments are reduced and their temperature dependences are more pronounced. Magnon excitation is stronger at the Co2MnSi / Al-O interface compared with Co-Fe-B based tunnel junctions and bulk Co2MnSi. We suggest, that mainly this contributes to the larger bias voltage and temperature dependence of the TMR in the Co2MnSi based junctions by means of enhanced magnon-assisted tunneling. Furthermore, several fingerprints of the ideal Co2MnSi bandstructure of atomically ordered Co2MnSi films are revealed by the XAS-, XMCD- and XPS-investigations in accordance with SPR-KKR calculations. Finally, we suggest that the observed inversion of the TMR effect occuring when electrons are tunneling from the Co-Fe into the atomically ordered Co2MnSi electrode is the most striking bandstructure effect.