Date of Award
Doctor of Philosophy
Materials Science and Engineering
The magnetic susceptibility of pure scandium and lutetium and several scandium-hydrogen and lutetium-hydrogen alloys was measured in the 2-300 K temperature range. The pure scandium samples were electrotransport purified single crystals while the electrotransport purified lutetium and rare earth-hydrogen alloys were polycrystalline. Measurements were made on a microcomputer-controlled magnetic susceptibility apparatus utilizing the Faraday method;The results for pure scandium show that the maximum and minimum in the susceptibility discovered by earlier experiments at Ames Laboratory are enhanced as the impurity level of iron in scandium decreases. Correlations of the low-temperature heat capacity data with the magnetic susceptibility results suggest the purity is now good enough to measure properties intrinsic to scandium, and are not due to impurity effects. The Stoner enhancement factor, calculated from low-temperature heat capacity data, susceptibility data, and band-structure calculations show scandium to be a strongly enhanced paramagnet. Below 2 K, the magnetic anisotropy between the hard and easy directions of scandium decreases linearly with decreasing temperature, tending toward zero at 0 K. The large increase in the susceptibility of scandium at lower temperatures shows that scandium is tending toward magnetic ordering;The pure lutetium and lutetium-hydrogen alloys showed an^anisotropy in susceptibility versus orientation of the samples.^Therefore, the samples were not random polycrystalline samples^and are not as reliable for absolute measurements. Pure lutetium^shows the shallow maximum and minimum observed earlier by^researchers at Ames Laboratory, but the increase in susceptibility^at low temperatures is larger than previously observed. The^susceptibility-composition dependence of the lutetium-hydrogen^alloys also did not match the results reported by other researchers,^but this can be attributed to the anisotropy of the samples. Thesusceptibility-composition dependence does not match thecomposition dependence of the electronic specific heat constantbelow 150 K, showing the electronic specific heat is being affected;by terms other than phonon-electron and pure electron-electron interactions;*DOE Report IS-T-1040. This work was performed under ContractNo. W-7405-Eng-82 with the U.S. Department of Energy.
Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/
Roger Joseph Stierman
Stierman, Roger Joseph, "The magnetic susceptibility of scandium-hydrogen and lutetium-hydrogen solid solution alloys from 2-300 K " (1982). Retrospective Theses and Dissertations. 8389.