Superconductivity on the border of weak itinerant ferromagnetism in UCoGe

N. T. Huy; A. Gasparini; D. E. de Nijs; Y. Huang; J. C. P. Klaasse; T. Gortenmulder; A. de Visser; A. Hamann; T. Gorlach; H. v. Lohneysen

doi:10.1103/physrevlett.99.067006

arXiv · 0708.1388

Superconductivity on the border of weak itinerant ferromagnetism in UCoGe

N. T. Huy·A. Gasparini·D. E. de Nijs·Y. Huang·J. C. P. Klaasse·T. Gortenmulder·A. de Visser·A. Hamann·T. Gorlach·H. v. Lohneysen

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Abstract

We report the coexistence of ferromagnetic order and superconductivity in UCoGe at ambient pressure. Magnetization measurements show that UCoGe is a weak ferromagnet with a Curie temperature T_{C}= 3 K and a small ordered moment $m_{0}$= 0.03 $μ_B$. Superconductivity is observed with a resistive transition temperature T_{s} = 0.8 K for the best sample. Thermal-expansion and specific-heat measurements provide solid evidence for bulk magnetism and superconductivity. The proximity to a ferromagnetic instability, the defect sensitivity of T_{s}, and the absence of Pauli limiting, suggest triplet superconductivity mediated by critical ferromagnetic fluctuations.

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N. T. Huy, A. Gasparini, D. E. de Nijs, Y. Huang, J. C. P. Klaasse, T. Gortenmulder, A. de Visser, A. Hamann, T. Gorlach, H. v. Lohneysen. 2007-08-10. Superconductivity on the border of weak itinerant ferromagnetism in UCoGe. https://doi.org/10.1103/physrevlett.99.067006

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