Partial Quenching of Rare Earth Moment in Cubic Laves Intermetallic Compounds

Abstract

Measurements of the low‐temperature (0.1° to 1.0°K) heat capacities of several cubic Laves intermetallic compounds containing praseodymium indicate the presence of a substantial nuclear hyperfine contribution to the specific heat. It is possible to relate the magnitude of this contribution to the magnetic moment carried by the Pr³⁺ ion in each of the materials studied. The moments deduced in this way are PrNi₂, 0.582±0.006; PrCo₂, 2.18±0.05; PrAl₂, 2.65±0.03 μ_B. These are each significantly less than the free Pr³⁺ ionic moment of 3.20 μ_B. The results are discussed in terms of a theory of Bleaney and it is concluded that the crystalline electric field is the same in PrCo₂ and PrNi₂, the large moment in the former being due to a larger exchange interaction. In the case of PrAl₂, the data indicate an accidental degeneracy in the crystalline field ground state.