Nuclear specific heat of bcc sup 3He near the magnetic-ordering transitions.

Precise specific-heat measurements were made on low density samples of bcc sup 3He in the vicinity of the various magnetic ordering transitions. The data obtained for magnetic fields of 0, 6 and 10 kOe span the temperature range 0.6 to 10 mK. At H = 0, the data exhibit an extremely sharp peak indicative of a first order transition. Below T sub N the specific heat is proportional to T sup 3 and yields a spin wave velocity (v sub (spin) in excellent agreement with a previous determination. Above T sub N, the results show no anomalous satellite peaks as seen in other experiments and as suggested by theoretical calculations. Within the precision of the measurements, the effect of changing the density is only to rescale the temperature. The data obtained at 6 and 10 kOe, when plotted as a function of T/T sub c nearly fall on a universal curve with a shape characteristic of a lambda-type transition.