Quantum tricritical fluctuations driving mass enhancement and reentrant superconductivity in URhGe

Tokunaga, Yo  ; Aoki, Dai*; Mayaffre, H.*; Krmer, S.*; Julien, M.-H.*; Berthier, C.*; Horvati, M.*; Sakai, Hironori   ; Kambe, Shinsaku  ; Hattori, Taisuke; Araki, Shingo*

Metamagnetism is in itself quite interesting phenomena, especially in a system with itinerant f-electrons. Unconventional states observed in the vicinity of the metamagnetic transition have been the subject of a number of recent publications. The object of this study is to elucidate the interplay between superconductivity and metamagnetism in URhGe. The nature of the metamagnetism becomes particularly important in ferromagnetic superconductors URhGe and UCoGe, since it is likely related to the pairing mechanism for their unconventional superconductivity. Here we report the result of our Co-NMR study on URhCoGe and discuss the origin of the field induced superconducting phenomenon observed in high fields around 12 T.