Regensburg 2004 – wissenschaftliches Programm

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MA: Magnetismus

MA 13: Poster:Schichten(1-23),Spinabh.Trsp(24-41),Exch.Bias(42-56),Spindyn.(57-67),Mikromag.(68-76),Partikel(77-90),Spinelektr.(91-97),Elektr.Theo.(98-99),Mikromag+PhasÜ+Aniso.(100-105),Magn.Mat.(106-118),Messmethod.(119-121),Obflm.+Abbverf.(122-123)

MA 13.29: Poster

Dienstag, 9. März 2004, 15:00–19:00, Bereich A

Properties of CMR-manganite films: Pr0.7Ca0.3MnO3 — •Wilko Westhäuser, Karsten Guth, Harald Jarzina, and Christian Jooss — Institut für Materialphysik, Universität Göttingen, Tammannstrasse 1, 37077 Göttingen, Germany

The CMR-effect describes a colossal drop in resistance caused by a phase transition from a charge-ordered antiferromagnetic state to a charge-delocalized ferromagnetic state. As the charge-ordered state of Pr0.7Ca0.3MnO3 is unstable under external perturbations, this transition can be switched by applying an electrical field, a magnetic field or using photon exposure.

Mixed powder of Pr6O11, CaCO3 and MnO3 with a defined ratio was calcined in air at 1050C for 48h and then pressed into a 25-mm diameter target. By using pulsed laser deposition, thin films were grown on single-crystalline SrTiO3-substrates (001). The calcined powder and the ablated thin films were analysed by XRD, DSC, REM and EDX to determine the crystallographic structure and the chemical composition.

Transport properties, in particular the metallic-insulator transition in electrical fields, are analysed as a function of temperature.