Electronic structure resistance anomalies

PrCu2 shows hardly any anomaly while a marked anomaly is observable in the resistivity. The resistivity measurements on a PrCu2 single crystal performed by Andres et al. (1976) show strong anisotropic behaviour for the a, b, and c direction of this orthorhombic structure. Because of the temperature-independent nature of this anisotropic behaviour Andres et al. (1976) conclude that the anisotropy in the resistivity is due to the anisotropy of the Fermi surface and not due to anisotropy in the scattering cross section between conduction electrons and f-electrons. 

The compound CeBeia crystallizes in the cubic NaZnja structure and has a lattice constant which suggests an intermediate Ce valence (Shoemaker et al., 1952). The magnetic susceptibility of CeBe (Cooper et al., 1971 Bucher et al., 1975a Borsa and Olcese, 1973) shows no evidence of magnetic order and is very similar to the susceptibility of CeSna. The electronic specific heat coefficient (Cooper et al., 1971) is 115 mJ/mole-K and there is a large peak in the thermoelectric power of 60/iV/K at 120 K. The electrical resistivity of CeBe has no sharp anomalies but at room temperature the resistance rise is slower than T. Borsa and Olcese (1973) measured the nuclear magnetic resonance and relaxation rate of the Be nucleus in CeBeu. They interpreted their data in terms of a variable Ce valence with Ce -Ce resonance lifetime of order 10" sec. 

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