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
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 JK. These results could be used to address
part of the experimental data for the compound,
when
.
PACS: 64.60.Cn – Order-disorder transformations; statistical mechanics of model systems / 75.10.Nr – Spin-glass and other random models / 75.30.Mb – Valence fluctuation, Kondo lattice, and heavy-fermion phenomena
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2002