NQR/NMR study of Zn-doped CeCoIn

Zn置換CeCoInにおける核四重極共鳴, 核磁気共鳴を用いた研究

酒井 宏典   ; 服部 泰佑; 比嘉 野乃花; 徳永 陽  ; 神戸 振作  ; Ronning, F.*; Zhu, J.-X.*; 鈴木 康平*; 大島 佳樹*; 横山 淳*

Sakai, Hironori; Hattori, Taisuke; Higa, Nonoka; Tokunaga, Yo; Kambe, Shinsaku; Ronning, F.*; Zhu, J.-X.*; Suzuki, Kohei*; Oshima, Yoshiki*; Yokoyama, Makoto*

微視的に量子臨界金属CeCoInの非磁性元素置換効果を調べるために核四重極共鳴(NQR)法を用いた。CdやZnの置換で長距離反強磁性秩序が誘起される。核磁気緩和率測定により、置換子周りの不均一な電子状態を明らかにした。講演では、Zn置換系の結果を示しながら、本系の超伝導と反強磁性秩序の共存についても議論する。

We have used Nuclear Quadrupole Resonance (NQR) to probe microscopically the response of prototypical quantum critical metal CeCoIn to substitutions of small amounts of Cd or Zn for In. Such non-magnetic Cd or Zn substitutions induce a long range antiferromagnetism. In the case of Cd substitutions, approximately half of the Cd substituents induce local Ce moments in their close proximity, as observed by site-dependent longitudinal nuclear spin relaxation rates . In the paramagnetic state, the values of at the main peak position are similar to those in the pure CeCoIn, while those are enhanced at the skirt position of spectrum. We will discuss about the heterogeneous electronic state realized in such a Zn substituted system and discuss about the coexistence of superconductivity with the antiferromagnetism, as well.