NMR study on a single crystal of URhGe

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

Ferromagnetism is incompatible in general with superconductivity (SC) with singlet spin pairs, since a strong exchange field in ferromagnetic state forces the spin pairs to align in the same direction. In contrast, fluctuation of ferromagnetic moments has been supposed to create a binding force between quasi-particles with triplet spin. Such an unconventional spin-triplet state, mediated by ferromagnetic fluctuations, is now expected to be realized in a family of uranium based compounds, UGe, URhGe and UCoGe, so far the only fully established examples of ferromagnetic superconductors in which uniform SC is realized deep inside the ferromagnetic states. To elucidate the mechanism of this exotic SC, we have prepared a URhGe single crystal and performed nuclear magnetic resonance (NMR) experiments.