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MA: Fachverband Magnetismus
MA 28: Magnetic Materials I
MA 28.2: Talk
Wednesday, April 2, 2014, 15:15–15:30, HSZ 04
Double exchange via t2g orbitals and Jahn-Teller effect in ferromagnetic La0.7Sr0.3CoO3 probed by epitaxial strain — •Dirk Fuchs, Michael Merz, Peter Nagel, Rudolf Schneider, Stefan Schuppler, and Hilbert von Löhneysen — Karlsruhe Institute of Technology, Karlsruhe, Germany
The magnetic exchange in hole-doped ferromagnetic cobaltates is investigated by studying the magnetic and electronic properties of La0.7Sr0.3CoO3 films as a function of epitaxial strain. We found a strong-coupling double exchange mechanism between Co3+ and Co4+ high-spin states mediated by t2g electrons in contrast to the moderate coupling provided by the eg-exchange in manganites. The strong sensitivity of the Curie temperature TC to the bulk compression can be explained by the small bandwidth of the t2g-derived states. A strain-induced Jahn-Teller effect is likewise observed. The experimental results clarify the magnetic exchange mechanism in the cobaltates.