Magnetic Order Beyond RKKY in the Classical Kondo Lattice

Abstract

We study the Kondo lattice model of band electrons coupled to classical spins, in three dimensions, using a combination of variational calculation and Monte Carlo. We use the weak coupling `RKKY' window and the strong coupling regime as benchmarks, but focus on the physically relevant intermediate coupling regime. Even for modest electron-spin coupling the phase boundaries move away from the RKKY results, the non interacting Fermi surface no longer dictates magnetic order, and weak coupling `spiral' phases give way to collinear order. We use these results to revisit the classic problem of 4f magnetism and demonstrate how both electronic structure and coupling effects beyond RKKY control the magnetism in these materials.

6 pages, 4 figs. Improved figures, expanded captions. To appear in Europhys. Lett

References in corpus (7)

• Theory of ferromagnetic (III,Mn)V semiconductors
• Critical Temperature of Ferromagnetic Transition in Three-Dimensional Double-Exchange Models
• Monte Carlo Simulations for the Magnetic Phase Diagram of the Double Exchange Hamiltonian
• Monte Carlo determination of the phase diagram of the double-exchange model
• T=0 Phase Diagram of the Double-Exchange Model
• Transport and Localisation in the Presence of Strong Structural and Spin Disorder
• Magnetic phase diagram of the Kondo lattice model with quantum localized spins

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• Spin-spiral states in undoped manganites
• Low-temperature magnetic properties of the Kondo lattice model in one dimension
• A new route to enhance the ferromagnetic transition temperature in diluted magnetic semiconductors
• Impact of Next-Nearest-Neighbor hopping on Ferromagnetism in Diluted Magnetic Semiconductors
• Mott transition and anomalous resistive state in the pyrochlore molybdates
• The ground state phase diagram of the diluted ferromagnetic Kondo-lattice model
• Non-collinear Magnetic Order in the Double Perovskites: Double Exchange on a Geometrically Frustrated Lattice
• Decision making by Berry's flux