Phase transitions in NdNiPb and Nd5NiPb3.

We report magnetic and thermodynamic measurements for NdNiPb and Nd5NiPb3. High-temperature Curie-Weiss fits yield effective moments per Nd of 3.59μB for NdNiPb and 3.70μB for Nd5NiPb3. These are close to the Nd3+ ionic moment, 3.62μB, showing that Ni is nonmagnetic in both cases. For NdNiPb a peak seen in both the magnetization and specific heat at 3.5 K indicates an antiferromagnetic transition at that temperature. Specific heat measurements show this transition to be formed from crystal-field-split Nd magnetic levels, and a fit yields values for crystal field splitting. Nd5NiPb3 exhibits two magnetic transitions, an antiferromagnetic transition at 42 K, and an apparently weak-ferromagnetic canting transition at 8 K. These are confirmed by specific heat measurements. M-H curves show metamagnetism at temperatures between the two magnetic transitions. [ABSTRACT FROM AUTHOR]