Regensburg 2007 – scientific programme

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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 15.47: Poster

Tuesday, March 27, 2007, 15:00–19:00, Poster A

Low-temperature tunneling magneto-resistance on LSMO-based junctions with organic barrier — •Hartmut Vinzelberg, Dieter Elefant, Joachim Schumann, Kathrin Dörr, Ramesh Gangineni, and Bernd Büchner — IFW Dresden, P.O. Box 270116, D-01171 Dresden, Germany

In analogy to the initiative work [1] on giant magneto-resistance in organic spin-valves LSMO-based junctions with an Alq₃-spacer were investigated with the aim to understand the transport behaviour in these new magnetic switching elements. The field and temperature dependence of the magneto-resistance of the prepared elements confirm the experimental observations in [1]. The described spin-valve effects at 4.2 K have been observed in a broad resistance interval from kΩ to MΩ-range without systematic area dependence. In some samples the magneto-resistance changes sign as a function of the bias voltage.

The observed similarity in the bias voltages dependences in comparison with (i) conventional MTJs with Al₂O₃ or MgO barriers and (ii) ferromagnetic contacted carbon nanotubes as well as the insulating nature of Alq₃ characterized by trapped-charge-limited conductivity [2] suggest to describe the found effects within a classical tunnelling concept. The proposed model implies the realization of the spin-dependent transport via local tunnelling paths embedded in the LSMO/Alq₃/Co sandwich structure.

[1] Z.H. Xiong et al., Nature 427, 821(2004)

[2] P.E. Burrows et al., J. Appl. Phys. 79, 7991(1996)