Low-Temperature Magnetic Studies of Uranium Hydride, Uranium Deuteride, and Uranium Dioxide

A study of magnetization as a function of temperature and magnetic field has been carried out for uranium hydride, uranium deuteride, and uranium dioxide at temperatures from 300°K to 1.3°K and in magnetic fields from 60 000 gauss down to zero field. The apparent saturation magnetization for the samples of beta-uranium hydride used is 1.18±0.03 Bohr magnetons per atom of uranium and for one sample of uranium deuteride is 0.98±0.03 Bohr magneton per atom of uranium. The magnetic moment of uranium dioxide, limited by what may be antiferromagnetic ordering, is about 0.025 Bohr magneton per atom of uranium at 35 000 gauss and 1.3°K. This result makes possible corrections for the moments of U${\mathrm{H}}_3$ and U${\mathrm{D}}_3$ on the basis of a known oxygen content or an estimate of the oxide impurity on the basis of apparent saturation. A high zero-field remanent magnetization (over 50% of the saturation magnetization for a spherical sample) is observed, attesting to the pronounced magnetic hardness of beta-uranium hydride. Analytic expressions have been worked out for magnetization as a function of temperature for zero magnetic field and 11 500 gauss, leading to a paramagnetic $\theta$ of 180°K and a ferromagnetic $\theta$ of 168°K. An estimate of 2×${10}^6$ gauss is made for the molecular field in U${\mathrm{O}}_2$.