Berlin 2005 – wissenschaftliches Programm

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MA: Magnetismus

MA 20: Poster:Schichten(1-29),Spintrsp(30-45),Ex-Bias(46-63),Spindyn(64-75),Mikromat.(76-80),Cluster(81-94),Abbv.(95-99),Obflm(100-02),SpElek.(103-09),E-Theo(110-14),Mikromag.(115-16),Spin+PÜ(117-26),Mag.Mat.(127-51),Meth.(152-55),Mol.Mag(156-59),Kondo(160-65

MA 20.42: Poster

Montag, 7. März 2005, 14:00–18:00, Poster TU C

Scanning Tunneling Spectroscopy on La_0.7Ca_0.3MnO₃ — •Sigrun A. Köster, Lakshamana Sudheendra, Vasily Moshnyaga, Bernd Damaschke, and Konrad Samwer — I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

Manganites show the colossal magnetoresistance effect (CMR), which already has been very well investigated. The main effect is observed at the temperature induced transition from a ferromagnetic metallic to an insulating behavior. According to the percolation model of Dagotto et al. [1] two different phases, an insulating and conducting one, exist in parallel. In our work we can show by scanning tunneling spectroscopy, that low resistivity and high resistivity regions do exist in the samples. These depend on several parameters like the microstructure of the samples, temperature of magnetic fields. Our investigations concentrate on achieving a more detailed picture of these phases and their origin.

[1] E. Dabotto, T. Hotta, A. Moreo, Physics Reports 344, (2001).