AN ELECTRICAL-RESISTIVITY STUDY OF CE2FE16.8 AND THE CE2FE17-XALX ANDCE2FE17-XSIX SOLID-SOLUTIONS

Electrical resistivity measurements have been carried out between 20 a nd 300 K on Ce2Fe16.8, on the Ce2Fe17-xAlx solid solutions, with x = 0 .4, 1, 2, 5, 6, 8, and 9, and on the Ce2Fe17-xSix solid solutions, wit h x = 0.2, 0.4, 1, and 2, with the four probe method. The temperature dependence of the resistivity of Ce2Fe16.8 shows an inflection at 110 K, a feature which is also observed in the temperature dependence of t he magnetization and is related to a magnetic phase transition from a helical structure, above 110 K, to a fan structure, below 110 K. The t emperature dependence of the resistivity of Ce2Fe16.8 is characteristi c over the investigated temperature range of weak antiferromagnetic be havior with incommensurate periodicity as has been observed in the ear lier neutron diffraction study. The resistivity of Ce2Fe17-xAlx increa ses with temperature in agreement with a density of states at the Ferm i level dominated by the d band. For a given temperature, the resistiv ity increases substantially and regularly with x for both series of so lid solutions because of an increase in the number of conduction elect ron scattering potentials. This increase in resistivity also correspon ds to a decrease in the number of conduction electrons due to their in creasing transfer into the localized cerium 4f orbitals as the cerium valence state changes from a mixture of trivalent and tetravalent in C e2Fe17 to predominantly trivalent in Ce2Fe17-xAlx and Ce2Fe17-xSix wit h increasing x. (C) 1997 American Institute of Physics.