Superconductivity in the Heusler alloy Pd₂YbPb

Magnetization and resistivity measurements have been carried out on the Heusler alloy Pd₂ YbPb in the temperature range 2-300 K. Both low-field dc susceptibility and resistivity show that this material undergoes a superconducting transition at 2.85 K. The presence of superconductivity was also confirmed by the Meissner effect observed at temperatures below 3 K. The temperature dependence of the susceptibility and resistivity have been accounted for on the basis of a crystal electric field with a Γ₇ ground state. Both measurements suggest that the energy splitting between a Γ₇ doublet and Γ₈ quartet, the first excited state, is about 65 K. However, the energy splitting between Γ₇ and Γ₆ (a doublet at highest energy) deduced from the resistivity data is 165 K, while the susceptibility data yield 355 K. We ascribed this discrepancy to the poor fitting quality of susceptibility at higher temperatures. We compare the results with those published in the literature for the isoelectronic Heusler compound Pd₂ YbSn.