Spin wave dispersion softening in the ferromagnetic Kondo lattice model for manganites

Abstract

Spin dynamics is calculated in the ferromagnetic (FM) state of the generalized Kondo lattice model taking into account strong on-site correlations between e_g electrons and antiferromagnetic (AFM) exchange among t_{2g} spins. Our study suggests that competing FM double-exchange and AFM super-exchange interaction lead to a rather nontrivial spin-wave spectrum. While spin excitations have a conventional Dq^2 spectrum in the long-wavelength limit, there is a strong deviation from the spin-wave spectrum of the isotropic Heisenberg model close to the zone boundary. The relevance of our results to the experimental data are discussed.

6 RevTex pages, 3 embedded PostScript figures

References in corpus (8)

• Evolution of the low-frequency spin dynamics in ferromagnetic manganites
• Magnon Damping by magnon-phonon coupling in Manganese Perovskites
• Softening and Broadening of the Zone Boundary Magnons in Pr0.63Sr0.37MnO3
• Ferromagnetism in Electronic Models for Manganites
• Theory of anomalous magnon softening in ferromagnetic manganites
• Charge and magnetic order in two-orbital double-exchange model for manganites
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• Spin dynamics in the generalized ferromagnetic Kondo model for manganites

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• The Composite Operator Method (COM)
• Interacting spin waves in the ferromagnetic Kondo lattice model
• Study of the spin-$\frac{3}{2}$ Hubbard-Kondo lattice model by means of the Composite Operator Method
• Spin-wave softening and Hund's coupling in ferromagnetic manganites
• Magnon self energy in the correlated ferromagnetic Kondo lattice model: spin-charge coupling effects on magnon excitations in manganites
• The ground state phase diagram of the diluted ferromagnetic Kondo-lattice model