Spin Excitations in Doped Manganites
A.M. Oleśa and L.F. Feinerb
a Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland
and Max-Planck-Institut FKF, Heisenbergstrasse 1, 70569 Stuttgart, Germany
b Institute for Theoretical Physics, Utrecht University, 3584 CC Utrecht, The Netherlands
and Philips Research Labs, Prof. Holstlaan 4, 5656 AA Eindhoven, The Netherlands
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We generalize the double exchange to describe holes doped in degenerate eg orbitals in La1-xAxMnO3 manganites, where A are divalent alkaline earth ions. Assuming an orbital liquid of disordered eg orbitals we find isotropic ferromagnetic exchange interactions which increase with hole doping. The magnon dispersion agrees very well with the experimental data in ferromagnetic metallic manganites.
DOI: 10.12693/APhysPolA.97.193
PACS numbers: 75.30.Ds, 75.30.Et, 71.27.+a