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MA: Magnetismus
MA 25: Kondo/Schwere-Fermionen
MA 25.1: Talk
Tuesday, March 8, 2005, 12:30–12:45, TU A060
The split personality of the 5f-electrons in uranium intermetallics — •Arno Hiess — ILL, Grenoble, France
Information on the interplay between superconductivity and magnetism is key to our understanding of a large variety of materials such as high-temperature and heavy-fermion superconductors. Of importance are some uranium-based intermetallic compounds, in which a co-existence of both phenomena is observed at low T. Inelastic neutron scattering offers the possibility to measure the wavevector (q) and energy (E) dependent magnetic response. Comparing the magnetic response observed for the heavy-fermion superconductor UBe13, the magnetic superconductors UPd2Al3 and UNi2Al3 as well as for the itinerant antiferromagnet UGa3 the unusual but intriguingly similar dynamic magnetic properties of such compounds are discussed. The magnetic response is structured in q- and E-space. It shows overdamped as well as propagating components, attributed to different degrees of freedom of 5f electrons. Furthermore, the magnetic response in UPd2Al3 shows a T- and B-dependent behaviour that can be linked to the superconductivity. It reflects the characteristic properties of the electronic system and sheds light on the symmetry of the superconducting order parameter.