Comment on the proposed magnetic cooling of He3

We examine a recent proposal by Goldstein for producing very low temperatures by freezing He3 in the presence of magnetic fields. We conclude that the highly isotropic nature of solid He3 will completely suppress the particular cooling mechanism envisaged, but a related magnetothermal effect should be observable. At readily accessible temperatures this effect will be small, but below about 1 mK a potentially useful amount of magnetic cooling is predicted. The field required for the maximum cooling is about 70 kOe.