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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 15.37: Poster

Dienstag, 27. März 2007, 15:00–19:00, Poster A

Magnetoresistive effects in single LSMO:MgO grain-boundaries — •Markus Esseling, Vasily Moshnyaga, and Konrad Samwer — I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen

The LSMO:MgO nanocomposite system shows a low-field magnetoresistance up to 30% at low temperatures which is due to the spin polarized tunneling of the conducting electrons across the insulating MgO, which separates individual LSMO grains [1]. Up to now it is still unclear whether the interesting properties of the nanocomposites are a result of the averaging process over all involved grain-boundaries (GB) or are intrinsic to every GB. Therefore we prepared single LSMO:MgO grain-boundaries using SrTiO₃- and MgO-bicrystal substrates. Junctions of different width (50µm - 300nm) were defined by e-beam lithography and focussed ion beam etching across the GB. A strong influence of the junction width is observed on both the resistance and the magnetoresistance, indicating an inhomogeneous GB. Moreover we show that smallest structures across the GB offers a possibility to study current-induced switching effects in lateral systems, which can be compared to heterostructures.

[1] M. Esseling et al., Appl. Phys. Lett. 87 (2005) 082509

Supported by SFB 602, TP A2 and DFG Sa337/9-1