NMR shift measurements of Ga in unconventional superconductor PuRhGa

Sakai, Hironori   ; Tokunaga, Yo  ; Fujimoto, Tatsuya; Kambe, Shinsaku  ; Walstedt, R. E.; Yasuoka, Hiroshi; Aoki, Dai*; Homma, Yoshiya*; Yamamoto, Etsuji  ; Nakamura, Akio; Shiokawa, Yoshinobu; Nakajima, Kunihisa  ; Arai, Yasuo; Matsuda, Tatsuma; Haga, Yoshinori   ; Onuki, Yoshichika

Very recently, we have succeeded in NMR/NQR measurements for PuRhGa. PuRhGa is a superconductor with 9 K, which is isomorphic to PuCoGa with the higher =18 K. We have reported that PuRhGa is an unconventional superconductor with an anisotropic gap, through the measurement of NQR spin-lattice relaxation rate , while PuCoGa is also reported to be such an anisotropic superconductor. The Knight shift and of NMR under applied field for the normal state of PuRhGa suggest an anisotropic feature of hyperfine and/or spin fluctuation in this system. We will outline the superconducting state and report the nature of the normal state based on the basis of and results. The difference between PuRhGa and PuCoGa will be also discussed.