NMR study of hydrogen in ferromagnetic -UH3

NMR of protons in ferromagnetic -UH3 was observed at 4.2 and 85 K in zero external magnetic field. The line was centered at 0=19.4 MHz (T=85 K). This frequency yields a value of nf=(1.45±0.1)B for the uranium-ion magnetic moment. The large linewidth (6 MHz) could be explained by a distribution of the dipolar fields at the proton sites. The spectrum was also measured in an external field. The line shape agrees well with measurements made previously for paramagnetic -UH3. Line broadening in an external field is due to distribution of demagnetization fields. The spin-spin relaxation time T2=90 sec (at 4.2 K) is well explained by the proton-proton dipolar interaction. T2 becomes shorter at 85 K and is field dependent.