Non-Fermi-liquid scaling in heavy-fermion UCu{sub 3.5}Al{sub 1.5} and UCu{sub 3}Al{sub 2}
- Manuel Lujan Jr. Neutron Scattering Center, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65, 1018 XE Amsterdam (The Netherlands)
- Institute of Physics, Academy of Sciences, Na Slovance 2, 18 040 Prague 8, (The Czech Republic)
- The Harrison M. Randall Laboratory of Physics, University of Michigan, Ann Arbor, Michigan 48109-1120 (United States)
- National High Magnetic Field Laboratory, Pulsed Field Facility, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
- Department of Physics, San Diego State University, San Diego, California 92182 (United States)
- Intense Pulsed Neutron Source, Argonne National Laboratory, Argonne, Illinois 60439-4814 (United States)
We report on specific-heat, magnetic-susceptibility, high-field-magnetization, electrical-resistivity, and neutron-diffraction results on UCu{sub 3.5}Al{sub 1.5} (polycrystal) and UCu{sub 3}Al{sub 2} (polycrystal and single crystal). Our results indicate that both compounds crystallize in the hexagonal CaCu{sub 5} structure with ordered UCu{sub 2} planes separated by planes containing a statistical distribution of Al along with the remaining Cu atoms. At low temperatures, the specific heat and the magnetic susceptibility of both compounds are enhanced, but their temperature dependences are found to be distinct from expectations of Fermi-liquid theory. UCu{sub 3.5}Al{sub 1.5} does not order magnetically, and the low-temperature specific heat and magnetic susceptibility show scaling behavior ({ital C}/{ital T}{proportional_to}ln{ital T} and {chi}{proportional_to}{ital T}{sup {minus}1/3}) reminiscent of non-Fermi-liquid materials. For UCu{sub 3}Al{sub 2}, on the other hand, the low-temperature scaling of bulk properties is masked by an anomaly around 8{endash}10 K, which is presumably of magnetic origin. Single-crystal studies of UCu{sub 3}Al{sub 2} reveal a huge magnetic anisotropy with very different in-plane response compared to the {ital c}-axis response. Our data provide evidence that any temperature dependence of the magnetic susceptibility (and electrical resistivity) of polycrystalline material may be due to averaging anisotropic response over all crystallographic directions. The results are discussed in the context of findings from other non-Fermi-liquid materials. {copyright} {ital 1996 The American Physical Society.}
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States)
- DOE Contract Number:
- W-31109-ENG-38
- OSTI ID:
- 392018
- Journal Information:
- Physical Review, B: Condensed Matter, Vol. 54, Issue 17; Other Information: PBD: Nov 1996
- Country of Publication:
- United States
- Language:
- English
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