Field-induced Phenomena in Ferromagnetic Superconductors UCoGe and URhGe

Abstract

We review our recent studies on ferromagnetic superconductors, UGe2, URhGe and UCoGe, where the spin-triplet state with the so-called equal spin pairing is realized. We focus on experimental results of URhGe and UCoGe in which the superconductivity occurs already at ambient pressure. The huge upper critical field Hc2 on UCoGe for the field along the hard magnetization axis (b-axis) is confirmed by the AC susceptibility measurements by the fine tuning of field angle. Contrary to the huge Hc2 along the hard-magnetization axis, Hc2 along the easy-magnetization axis (c-axis) is relatively small in value. However, the initial slope of Hc2, namely dHc2/dT (H -> 0) both in UCoGe and in URhGe indicates the large value, which can be explained by the magnetic domain effect detected in the magnetization measurements. The specific heat measurements using a high quality single crystal of UCoGe demonstrate the bulk superconductivity, which is extended under magnetic field for the field along c-axis.

6 pages, 4 figures, proceedings of TOKIMEKI2011, to be published in J. Phys. Soc. Jpn. Suppl

References in corpus (6)

• Superconductivity on the border of weak itinerant ferromagnetism in UCoGe
• Ferromagnetism and Superconductivity in Uranium Compounds
• Field Re-entrant Superconductivity Induced by the Enhancement of Effective Mass in URhGe
• Possible Phase Transition Deep Inside the Hidden Order Phase of Ultraclean URu2Si2
• Properties of Ferromagnetic Superconductors
• Absence of Meissner State and Robust Ferromagnetism in the Superconducting State of UCoGe: Possible Evidence of Spontaneous Vortex State

Cited by in corpus (4)

• Magnetism and Superconductivity in Ferromagnetic Heavy Fermion System UCoGe under In-plane Magnetic Fields
• Superconducting Gap of UCoGe probed by Thermal Transport
• Multigap Superconductivity in the Ferromagnetic Superconductor UCoGe Revealed by Thermal Conductivity Measurements
• Spin-Triplet Superconductivity Induced by Longitudinal Ferromagnetic Fluctuations in UCoGe: Theoretical Aspect