Eur. Phys. J. B 30, 419-425 (2002)
https://doi.org/10.1140/epjb/e2002-00398-y

Spin glass and ferromagnetism in Kondo lattice compounds

¹ Departamento de Física – UFSM, 97105-900 Santa Maria, RS, Brazil
² Departamento de Matemática – UFSM, 97105-900 Santa Maria, RS, Brazil
³ Instituto de Física – UFRGS, 91501-970 Porto Alegre, RS, Brazil
⁴ Laboratoire de Physique des Solides, Université Paris-Sud, bâtiment 510, 91405 Orsay, France

Corresponding author: ^a ggarcia@ccne.ufsm.br

Received: 24 June 2002
Published online: 31 December 2002

Abstract

The Kondo lattice model has been analyzed in the presence of a random inter-site interaction among localized spins with non zero mean J₀ and standard deviation J. Following the same framework previously introduced by us, the problem is formulated in the path integral formalism where the spin operators are expressed as bilinear combinations of Grassmann fields. The static approximation and the replica symmetry ansatz have allowed us to solve the problem at a mean field level. The resulting phase diagram displays several phase transitions among a ferromagnetically ordered region,a spin glass one, a mixed phase and a Kondo state depending on J₀, J and its relation with the Kondo interaction coupling J_K. These results could be used to address part of the experimental data for the compound, when .