Evidence for weak spin-orbit interaction experienced by Cooper pairs in the spin-triplet superconductor UPt; Pt-NMR study

スピン三重項超伝導体UPtのクーパー対が感じる弱いスピン軌道相互作用の証拠; Pt核磁気共鳴による研究

青山 泰介*; 小手川 恒*; 木村 憲彰*; 山本 悦嗣  ; 芳賀 芳範   ; 大貫 惇睦*; 藤 秀樹*

Aoyama, Taisuke*; Kotegawa, Hisashi*; Kimura, Noriaki*; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika*; To, Hideki*

Pt-NMR measurements under magnetic field () parallel to the -axis in the vicinity of the upper critical field have been carried out on the heavy-fermion superconductor UPt. The quasiparticle spin susceptibility was obtained from the measurements. The field dependence of the susceptibility suggests that the -vector freely rotates in magnetic field. It is therefore concluded that spin-orbit interaction, which confines the direction of the -vector with respect to the crystal axis, is weak in UPt.