[show abstract][hide abstract] ABSTRACT: The correlated metal UCoGe is a weak itinerant ferromagnet with a Curie temperature T
C=3K and a superconductor with a transition temperature T
s=0.6K. We review its basic thermal, magnetic—onthe macro and microscopic scale—and transport properties, as well as the
response to high pressure. The data unambiguously show that superconductivity and ferromagnetism coexist below T
s=0.6K and are carried by the same 5f electrons. We present evidence that UCoGe is a p-wave superconductor and argue that superconductivity is mediated by critical ferromagnetic spin fluctuations.
p-wave superconductor-Magneticquantum critical point-Critical spin fluctuations
Journal of Low Temperature Physics 04/2012; 161(1):134-147. · 1.18 Impact Factor
[show abstract][hide abstract] ABSTRACT: We report a high-pressure single crystal study of the superconducting ferromagnet UCoGe. Measurements of the ac susceptibility and resistivity under pressures up to 2.2 GPa show ferromagnetism is smoothly depressed and vanishes at a critical pressure p(c) = 1.4 GPa. Near the ferromagnetic critical point superconductivity is enhanced. Upper-critical field measurements under pressure show B(c2)(0) attains remarkably large values, which provides solid evidence for spin-triplet superconductivity over the whole pressure range. The obtained p-T phase diagram reveals superconductivity is closely connected to a ferromagnetic quantum-critical point hidden under the superconducting "dome."