Due to the particular geometry of the kagom\'e lattice, it is shown that antisymmetric Dzyaloshinsky-Moriya interactions are allowed and induce magnetic ordering. The symmetry of the obtained… Expand

A model of localized highly frustrated ferromagnetism is presented: kagom\'e spin ice. Using analytical and Monte Carlo calculations its massive ground-state entropy is evaluated. Monte Carlo… Expand

The Anderson model is studied in the limit U to infinity using a Green function decoupling procedure. It is shown that the solution gives the correct results in the intermediate valence case, and in… Expand

The quantum pyrochlore antiferromagnet is studied by perturbative expansions and exact diagonalization of small clusters. We find that the ground state is a spin-liquid state: The spin-spin… Expand

We discuss the phase diagram of the Kondo lattice: we generalize to the lattice a method proposed by Yoshimori and Sakurai for the single-impurity Kondo problem; this method transforms the Kondo… Expand

We study the energy spectrum of magnons in a ferromagnet with topologically nontrivial magnetization profile. In the case of inhomogeneous magnetization corresponding to a metastable state of… Expand