Normal and superconducting state properties of U6Fe at low temperatures and high magnetic fields

L. E. Delong, G. W. Crabtree, L. N. Hall, H. Kierstead, H. Aoki, S. K. Dhar, K. A. Gschneidner, A. Junod

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14 Citations (Scopus)

Abstract

High purity U6Fe polycrystals with a resistance ratio rrr=9 at T=4 K are found to exhibit a record onset temperature (T0 > 4.0 K) to superconductivity for U materials. Our measured values of the electronic coefficient of heat capacity γ*=(150±3) mJ/mol · K2, the mean Debye temperature Θ(T→0)=166 K and the normalized jump in heat capacity at Tc, Δ/γTc=2.3±0.1, are all in good agreement with previous work † L.E Delong et al.Physics.Rev.Lett.51(1983)312., and suggest that U6Fe is a strong-coupled superconductor. Resistive upper critical field measurements on high purity samples revealed a pronounced S-shaped curvature of Hc2(T) and evidence for anisotropy, similar to effects seen in UPt3 † L.E Delong et al.Physics.Rev.Lett.51(1983)312., but not observed in lower purity U6Fe samples † L.E Delong et al.Physics.Rev.Lett.51(1983)312.. We find Hc2(0) > 10T and transition widths ΔTc∝H 1 2 at moderate fields, followed by an abrupt increase in ΔTc for H>8T. Our Hc2 data cannot be explained by existing theoretical models. Preliminary heat capacity measurements in magnetic fields 0≤H≤10T suggest that γ* may decrease by ≈10% at H=10 T. These results and electrical resistivity data will be discussed in terms of a potential charge density wave instability in U6Fe at T{less-than or approximate}110 K.

Original languageEnglish
Pages (from-to)81-85
Number of pages5
JournalPhysica B+C
Volume135
Issue number1-3
DOIs
Publication statusPublished - 1985 Dec 2

ASJC Scopus subject areas

  • Engineering(all)

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