P-NMR study of the neptunium-based filled-skutterudite NpFeP

Tokunaga, Yo  ; Aoki, Dai*; Homma, Yoshiya*; Sakai, Hironori   ; Chudo, Hiroyuki ; Kambe, Shinsaku  ; Matsuda, Tatsuma; Ikeda, Shugo; Yamamoto, Etsuji  ; Nakamura, Akio; Haga, Yoshinori   ; Shiokawa, Yoshinobu*; Onuki, Yoshichika; Yasuoka, Hiroshi

P-NMR measurements have been performed on a single crystal of NpFeP which is the first crystallized transuranium filled-skutterudite compound. The field-orientation dependence of the hyperfine interaction has been measured using the single crystal, and the results compared with those obtained previously in isostructural compounds UFeP and PrFeP. We have also measured the field and temperature dependence of the nuclear spin-lattice relaxation rate in several fields between 1.8 and 8 T at temperatures between 4.2 and 300 K. The results are discussed on the basis of a localized picture for the 5f electrons.