Structural chemistry and magnetic behavior of binary uranium silicides |
| |
| Affiliation: | 1. Institut für Physikalische Chemie der Universität Wien, Währingerstrasse 42, A-1090 Wien, Austria;2. Laboratoire de Chimie du Solide et Inorganique Moléculaire, U.R.A. C.N.R.S. 254, Université de Rennes I, Avenue du Général Leclerc, F-35042 Rennes, France;1. Department of Chemistry and Alexandra Navrotsky Institute for Experimental Thermodynamics, Washington State University, Pullman, WA, 99164, United States;2. Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, United States;3. Center for High Pressure Science & Technology Advanced Research, Shanghai, 201203, China;4. Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, United States;5. Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois, 60439, United States;6. Fusion and Materials for Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37830, United States;1. Earth and Environmental Sciences Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, United States;2. Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, United States;3. Department of Chemistry, Washington State University, Pullman, WA, 99164, United States;1. Materials Science and Technology Division, Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM, 87545, USA;2. Fuel Modeling and Simulation, Idaho National Laboratory, P.O. Box 1625, Idaho Falls, ID, 83415, USA;3. Westinghouse Electric Sweden AB, SE-721 63, Västerås, Sweden;4. Nuclear Futures Institute, Bangor University, Bangor, LL57 2DG, UK |
| |
| Abstract: | Binary uranium silicides have been thoroughly reinvestigated with respect to crystal chemistry and magnetic properties; for most compounds, magnetic studies have been carried out at low temperatures for the first time (2 to 300 K, 0 to 5 T). Formation of all known binary silicides has been confirmed: U3Si, U3Si2 (U3Si2-type), USi (USi-type), U3Si5 (defect AlB2-type), USi1.88 (defect ThSi2-type) and USi3 (Cu3Au-type). At the composition U3Si∼5 three different phases have been observed: the defect AlB2-type as well as a phase separation into two orthorhombically distorted Alb2-type related phases. USi2−x with the tetragonal defect ThSi2-type structure at its silicon poor phase boundary was found to be in equilibrium with USi2−x of the orthorhombic defect GdSi2 type. Precise U-U distances have been derived from X-ray single crystal counter data for U3Si2, USi, for the AlB2-type subcell of U3Si5, and for USi1.84 (defect ThSi2-type). From susceptibility measurements, a band type paramagnetism was observed for U3Si2, whereas a temperature independent paramagnetism was confirmed for USi3. Curie-Weiss paramagnetism was encountered within the investigated temperature range for U3Si5 and USi1.88. A modified Curie-Weiss law was revealed for USi with the USi-type, whereas ferromagnetic ordering at Tc = 125 K was observed for the oxygen stabilized “USi” with the FeB-type. Magnetism of the uranium silicides is discussed as a function of the distant dependent 5f-5f electron overlap and d-f electron hybridization. No superconductivity was observed above 2 K. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
