Berlin 2008 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 32: Postersession II: Spinstruct./Phase Trans. (1-10); Spinelectronics (11-15); Thin Films (16 - 36); Particles/Clusters (37-45); Multiferroics (46-54); Spindynamics/Spin Torque (55 - 76); Post Deadlines (77-79)

MA 32.32: Poster

Freitag, 29. Februar 2008, 11:15–14:00, Poster E

Scanning tunneling spectroscopy on La_0.75Ca_0.25MnO₃ thin film in external magnetic fields — •Thomas Mildner, Sigrun Köster, Bernd Damaschke, Vasily Moshnyaga, and Konrad Samwer — I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

Manganite thin films show a colossal magnetoresistance effect (CMR) combined with a metal-insulator transition (MIT). The MIT is observed not only as a function of temperature but also in an external magnetic field. The transition may be discussed in terms of an electronic phase separation with possible contributions of polaronic ordering.

In this work an A-site ordered La_0.75Ca_0.25MnO₃ thin film was grown by metalorganic aerosol deposition (MAD) technique on a MgO substrat. The scanning tunneling spectroscopy measurements were performed in UHV at various temperatures in the vicinity of the MIT and external magnetic fields. Regions with different tunneling conductivity at the Fermi level increases with external magnetic fields leading to a CMR-like effect also in the tunneling conductivity.

The work is supported by the DFG via SFB 602, TP A2