Regensburg 2007 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 18: Spindependent Transport II
MA 18.12: Vortrag
Mittwoch, 28. März 2007, 18:00–18:15, H22
Magnetotransport in thin LSMO:CeO2 nanocomposite films — •Markus Esseling1, Hamish Gordon2, Christian Stingl1, Kai Gehrke1, Vasily Moshnyaga1, and Konrad Samwer1 — 1I. Physikalisches Institut, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany — 2Cavendish Laboratory, J.J. Thomson Avenue, Cambridge CB3 0HE, UK
Due to the chemical phase separation of the highly spin-polarized manganite LSMO and the insulating CeO2 it is possible to prepare nanocomposite films. Using the columnar growth mode of the LSMO on Al2O3-substrates the microstructure of the films results in LSMO-grains which are separated by the CeO2-phase. Therefore the system builds a lateral TMR-structure.
(LSMO) 1−x:(CeO2) x nanocomposite films with a thickness ≈70nm were prepared by MAD-technique with 0 ≤ x ≤ 0,5. The temperature of the metal-insulator transition decreases systematically with increasing CeO2-content, whereas the influence on the Curie-temperature is not so strong. The system shows a low-field magnetoresistance (LFMR) up to 60% for the x = 0.2 sample, which is near the percolation threshold. To study the effect of the number of involved grains some samples were microstructured into current stripes of well-defined width. A strong influence on the temperature dependence of the resistance is observed, whereas the LFMR is nearly unchanged. The effect of the quality of the interfaces LSMO/CeO2 will be discussed.
Supported by SFB 602, TP A2 and DFG Sa337/9-1