Abstract
The duality between the localized and itinerant nature of magnetism in 5f-electron systems has been a long-standing puzzle. Here, we report inelastic neutron scattering measurements, which reveal both local and itinerant aspects of magnetism in a single-crystalline system of UPt2Si2. In the antiferromagnetic state, we observe a broad continuum of diffuse magnetic scattering with a resonancelike gap of ≈7 meV and the surprising absence of coherent spin waves, suggestive of itinerant magnetism. While the gap closes above the Néel temperature, strong dynamic spin correlations persist to a high temperature. Nevertheless, the size and temperature dependence of the total magnetic spectral weight can be well described by a local moment with J=4. Furthermore, polarized neutron measurements reveal that the magnetic fluctuations are mostly transverse, with little or none of the longitudinal component expected for itinerant moments. These results suggest that a dual description of local and itinerant magnetism is required to understand UPt2Si2 and, by extension, other 5f systems, in general.
| Original language | English |
|---|---|
| Article number | 057201 |
| Journal | Physical Review Letters |
| Volume | 121 |
| Issue number | 5 |
| DOIs | |
| State | Published - Jul 30 2018 |
Funding
We thank Guangyong Xu and T. J. Williams for helpful discussion on data analysis. This research at High Flux Isotope Reactor and Spallation Neutron Source of ORNL was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences, U.S. Department of Energy, and the Laboratory Directors Research and Development fund of ORNL. Cornell High Energy Synchrotron Source was supported by the NSF and NIH/National Institute of General Medical Sciences via NSF Award No. DMR-1332208. The work at Brookhaven National Laboratory was supported by the Office of Basic Energy Sciences, U.S. Department of Energy, under Contract No. DE-SC0012704.