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
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 Ce2Au
CoxSi3 compound.
PACS: 05.50.+q – Lattice theory and statistics; Ising problems / 64.60.Cn – Order disorder transformations; statistical mechanics of model systems
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2003
