A calorimetric measurement of the nuclear quadrupole coupling in pure, single crystal, rhenium metal

The nuclear contribution to the specific heat of Re has been measured in the temperature range 0.1°K – 0.5°K. The nuclear contribution has the expected A/T^2 dependence. We have found A = 0.061 ± 0.002 mJ°K/mole for H ∼ H_c increasing to A = 0.077 ± 0.004 mJ°K/mole at H = 12.5 Oe. On the basis of these results the resonant magnetic fields for possible NMR transitions are predicted