Dilute Kondo lattice

Some of the Kondo systems investigated in this section are not in fact dilute magnetic alloys. Instead they are Kondo lattices in which the magnetic moments lie on a sublattice of the RI compound (e.g. CeAy. The R-atom in all these compounds is Ce for which the d-f admixture interaction mentioned in section 3.1.2 is dominant. Such RI compounds are therefore Kondo systems in which eq. (30) for the resistivity holds. However, for temperatures T < Tr the magnetic moment is usually not totally compensated in a Kondo lattice since now there are too few conduction electrons to achieve full compensation on every magnetic lattice site. 

Kondo s treatnient omitted several important interaction terms but the latter authors were able to show that the thermopower depends in an interconnected manner on exchange coupling, potential scattering, and the range of the interaction (see Blatt et al., 1976). No theoretical work has as yet been done for Kondo lattices. However, the thermopower of CeAl2 which is a Kondo lattice does in fact show a giant thermopower anomaly similar to that found in dilute Kondo alloys. 

Thermal conductivity of systems with heavy fermions, intermediate valency of lanthanide ions, dilute and concentrated Kondo lattices... 

In a number of theoretical works the behaviour of k T) and UJ) of systems with concentrated (CKL) and dilute (DKL) Kondo lattices have been investigated (Fisher 1971, Nakamura et al. 1987, Bhattacharjee and Coqblin 1988, Cox and Grewe 1988,... 

As mentioned in the Introduction (section 1), the electrical resistivity, specific heat, magnetic susceptibility and thermoelectric power anomalies of concentrated lanthanide Kondo systems are qualitatively similar to those found in the dilute lanthanide systems discussed previously. However the importance of the concentrated systems is that they provide a totally new view of Kondo-like phenomena. Lattice constant. X-ray photoemission (XPS) and Mossbauer isomer shift measurements indicate a strong correlation between systems that exhibit Kondo-like anomalies and systems in which the lanthanide ion has a mixed or intermediate valence. By mixed valence we mean that there are two 4f electron configurations accessible to each rare earth ion (e.g., Ce -Ce, Eu -Eu ", Yb -Yb ). Phenomenologically the traditional... 

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