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Double-exchange model: phase separation versus canted spins

  • M.Yu. Kagan
  • D.I. Khomskii
  • M.V. Mostovoy

Abstract:

We study the competition between different possible ground states of the double-exchange model with strong ferromagnetic exchange interaction between itinerant electrons and local spins. Both for classical and quantum treatment of the local spins the homogeneous canted state is shown to be unstable against a phase separation. The conditions for the phase separation into the mixture of the antiferromagnetic and ferromagnetic/canted states are given. We also discuss another possible realization of the phase-separated state: ferromagnetic polarons embedded into an antiferromagnetic surrounding. The general picture of a percolated state, which emerges from these considerations, is discussed and compared with results of recent experiments on doped manganaties.

PACS. 75.10.-b General theory and models of magnetic ordering - 75.30.Mb Valence fluctuation, Kondo lattice, and heavy-fermion phenomena - 75.30.Kz Magnetic phase boundaries (including magnetic transitions, metamagnetism, etc.) 

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Copyright information

© EDP Sciences, Springer-Verlag, Società Italiana di Fisica 1999

Authors and Affiliations

  • M.Yu. Kagan
    • 1
  • D.I. Khomskii
    • 2
  • M.V. Mostovoy
    • 2
  1. 1.P.L. Kapitza Institute for Physical Problems, Kosygina Street 2, 117334 Moscow, RussiaRU
  2. 2.University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The NetherlandsNL

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