Magnetic ordering in Ce-La and Nd-La alloys

Abstract

Heat capacity, magnetic susceptibility, and electrical resistivity measurements have been made on a wide ranging set of Ce-La and Nd-La alloys. In the case of Ce it is found that less than 5 at. % of La will prevent the β (dhcp) to α (collapsed fcc) transition at T≲50 K. In the case of Nd-La only the dhcp allotrope is formed. Two magnetic ordering temperatures have been found for many of the samples. These are believed to be caused by antiferromagnetic ordering on the two different atomic sites in the dhcp structure, cubic and hexagonal. In both sets of alloys the two ordering temperatures coalesce into one for La concentrations ≳30%. Additional magnetic features in Ce-La alloys are explained by the formation of the fcc phase.

FCRD Advanced Reactor (Transmutation) Fuels Handbook

“…Petersen et al measured the low-temperature electrical resistivity of two La-Ce alloys and determined that the room-temperature electrical resistivity of an alloy with 70 at% La is ~ 67 Ω-cm and the roomtemperature electrical resistivity of an alloy with 22 at% La is ~74 Ω-cm [410]. These values are generally consistent with room-temperature electrical resistivities of α-La (61.5 Ω-cm) and γ-Ce (74.4 Ω-cm) in the CRC Handbook of Chemistry and Physics [17 Table 9].…”

“…Constant-pressure heat capacities of La-Ce alloys have been measured at temperatures below 300 K [410], and constant-volume heat capacities have been calculated at high pressures [328]. However, data on the heat capacities of La-Ce alloys at temperatures and pressures of interest for nuclear fuels are not available, and experimental investigation is required.…”