Unconventional heavy-fermion superconductivity of a new transuranium compound NpPdAl

Aoki, Dai*; Haga, Yoshinori   ; Matsuda, Tatsuma; Tateiwa, Naoyuki   ; Ikeda, Shugo; Homma, Yoshiya*; Sakai, Hironori   ; Shiokawa, Yoshinobu*; Yamamoto, Etsuji  ; Nakamura, Akio; Settai, Rikio*; Onuki, Yoshichika

We succeeded in growing a new transuranium compound NpPdAl with the tetragonal crystal structure by the Pb-flux method, and measured the electrical resistivity, specific heat, magnetic susceptibility and magnetization. NpPdAl is found to be a paramagnetic heavy-fermion superconductor with strong coupling. The upper critical field H at 0 K is large and highly anisotropic.