Non-Fermi liquid normal state of the heavy-fermion superconductor UBe 13

• Published in: Physica. C, Superconductivity Vol. 408; pp. 157 - 160
• Main Authors: Gegenwart, P., Langhammer, C., Helfrich, R., Oeschler, N., Lang, M., Kim, J.S., Stewart, G.R., Steglich, F.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-08-2004
• Subjects: Heavy-fermion superconductivity; Non-Fermi liquid behavior; UBe 13; Heavy-fermion superconductivity; Non-Fermi liquid behavior; UBe 13
• ISSN: 0921-4534; 1873-2143
• DOI: 10.1016/j.physc.2004.02.070

Non-Fermi liquid (NFL) behavior in the normal state of the heavy-fermion superconductor UBe
13 is studied by means of low-temperature measurements of the specific heat,
C, and electrical resistivity,
ρ, on a high-quality single crystal in magnetic fields up to 15.5 T. At
B=0, unconventional superconductivity forms at
T
c=0.9 K out of an incoherent state, characterized by a large and strongly temperature dependent
ρ(
T). In the magnetic field interval
4
T⩽B⩽10
T
,
ρ(
T) follows a
T
3/2 behavior for
T
c(
B)⩽
T⩽1 K, while
ρ is proportional to
T at higher temperatures. Corresponding non-Fermi liquid behavior is observed in
C/
T as well and hints at a nearby antiferromagnetic (AF) quantum critical point (QCP) covered by the superconducting state. We speculate that the suppression of short-range AF correlations observed by thermal expansion and specific heat measurements below
T
L≈0.7 K (
B=0) yields a field-induced QCP,
T
L→0, at
B=4.5 T.