Abstract
The specific heat of uranium mononitride was measured at temperatures from 1.3 to 4.6°K and was found to be of the form , where is 24.79±0.05 mJ and the Debye is 324±7°K. The large value of (35 times the value for copper) apparently results from the Fermi surface intersecting narrow electronic bands. The above values refer to a UN sample heat-treated in an atmosphere of nitrogen for 6.5 h at 2250°C. The same sample, before this heat treatment, had a measured mJ and K. The shift in may be due to a small change in stoichiometry caused by the heat treatment. Although the Debye temperature obtained from the present work, 324°K, is larger than previous specific-heat estimates of 276-289°K, it is lower than the value of 364°K obtained from velocity-of-sound measurements. No changes were observed in the specific heat upon application of magnetic fields up to 35 kG, suggesting the absence of any appreciable magnetic contribution to the total specific heat for temperature below 4.7°K.
- Received 8 July 1968
DOI:https://doi.org/10.1103/PhysRev.176.666
©1968 American Physical Society