Eur. Phys. J. B 34, 447-453 (2003)
https://doi.org/10.1140/epjb/e2003-00243-y

Spin glass and antiferromagnetism in Kondo-lattice disordered system

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, 91405 Orsay, France

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

Received: 9 April 2003
Published online: 9 September 2003

Abstract

The competition between spin glass (SG), antiferromagnetism (AF) and Kondo effect is studied here in a model which consists of two Kondo sublattices with a Gaussian random interaction between spins in different sublattices with an antiferromagnetic mean J₀ and standard deviation J. In the present approach there is no hopping of the conduction electrons between the sublattices and only spins in different sublattices can interact. The problem is formulated in the path integral formalism where the spin operators are expressed as bilinear combinations of Grassmann fields which can be solved at mean field level within the static approximation and the replica symmetry ansatz. The obtained phase diagram shows the sequence of phases SG, AF and Kondo state for increasing Kondo coupling. This sequence agrees qualitatively with experimental data of the Ce₂AuCo_xSi₃ compound.