Role of disorder in magnetic and conducting properties of U-Mo and U-Mo-H thin films

Crystal structure, magnetic and electrical properties of thin U-Mo films and their hydrides prepared by reactive sputter deposition from metallic targets were studied. The films are metallic but with high values of electrical resistivity. Both bcc U(0.7)9Mo(0.21) thin film and the hydride (UH3)(0.74)Mo-0.26 (beta-UH3 structure type) have a very strong texture. Superconductivity is identified below T-c = 0.55 K for U0.79Mo0.21. The critical field of 1.0 T is exceeding that of alpha-U (0.3 T). The hydride film (UH3)(0.74)Mo-0.26 is a ferromagnet with the Curie temperature T-C = 165 K, higher concentration of Mo somewhat reduces the TC value. Deposition on a cooled substrate reduces the grain size of the hydride, approaching the limit of amorphous state. The U-Mo films and hydrides exhibit the net negative temperature coefficient of resistivity, TCR = d(rho)/d(T), attributed to the randomness on atomic scale, yielding very strong scattering of electrons and weak localization.

Automated summary

The thin U-Mo films and their hydrides prepared by reactive sputter deposition from metallic targets exhibit metallic properties with high electrical resistivity. The films show superconductivity and ferromagnetism, with attributes such as strong texture and negative temperature coefficient of resistivity.