Electrical, magnetic, and thermal properties of UCu_5−xPt_x

Abstract

We report measurements of the structural and electronic properties of UCu_{5 −  x} Pt _x , a Pt-based analogue of the nFL system UCu_{5 −  x} Pd _x , in the concentration range 0≤ x ≤ 5. Forx ≤ 2.5 and x ≥ 4.5, the UCu_{5 −  x} Pt _x system crystallizes in the AuBe₅ structure, but is mixed phase in the range 2.5 < x < 4.5. We observe a rapid suppression of long range antiferromagnetic order for small concentrations of Pt. The electrical resistivity, DC magnetic susceptibility, and specific heat of UCu_{5 −  x} Pt _x in the concentration range 0.75 ≤ x ≤ 1 have temperature dependencies at low temperature (T ≤ 10 K) consistent with the non-Fermi liquid behaviour found in UCu_{5 −  x} Pd _x . Above x = 1, there is a transition from non-Fermi liquid behaviour to Fermi liquid behaviour with no observation of any spin glass behaviour.

Acknowledgements

This work was supported by the National Science Foundation under Grant No. DMR 00-72125 and the US Department of Energy under Grant No. DE-FG03-86ER-45230. This work was performed under the auspices of the US Department of Energy by University of California, Lawrence Livermore National Laboratory under contract No. W-7405-Eng-48.