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We report measurements of the low-temperature specific heat of CeB6 and discuss their significance in the light of earlier studies of this compound. The large specific heat above the antiferromagnetic ordering at 2. 31 K is interpreted with the aid of a decorated Ising model. This model permits us to combine exchange and crystal field interactions in a simplified, but exact, calculation of the thermodynamic properties of a magnetic system including the effects of fluctuations. The analysis gives independent support to t1:e proposal by Nickerson and White that the exchange in the crystal field excited state is substantially stronger than the ground-state exchange in CeB6. We also comment on the possibility of extending such an analysis to other magnetic rare-earth hexaborides.

Magnetic and transport measurements in ferromagnetic EuB6 show (a) evidence for a Fisher-Langer-type resistance anomaly near Tc, (b) that EuB6 may not be a simple ferromagnet, and (c) that the magnetic coupling might be influenced by a temperature-dependent conduction electron concentration.

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