Spin dynamics of heavy-fermion compound YbCoZn

重い電子系化合物YbCoZnにおけるスピンダイナミクス

金子 耕士   ; 吉内 伸吾*; 竹内 徹也*; 本多 史憲*; 摂待 力生*; 大貫 惇睦

Kaneko, Koji; Yoshiuchi, Shingo*; Takeuchi, Tetsuya*; Honda, Fuminori*; Settai, Rikio*; Onuki, Yoshichika

YbTZn is known to exhibit heavy-fermion behavior. In particular, YbCoZn shows extremely large electronic specific coefficient at ambient pressure. In order to get detailed insights into f-electron state in YbCoZn, neutron scattering experiments were carried out. In neutron inelastic spectra at 300 mK, strong quasielastic scattering together with an apparent peak at 0.6 meV was observed. With increasing temperature to 10 K, a broad peak comes up around 2.1 meV, whereas quasielastic response gets broader and the peak at 0.6 meV is buried in the quasielastic one. The observed quasielastic scattering can be ascribed as Kondo-type spin fluctuation with a characteristic energy scale of 0.3 meV. The observed peaks at 0.6 and 2.1 meV can be assigned as crystal-field excitations. Coexistence of both the quasielastic scattering and the sharp crystal-field excitations characterizes the f-electron state in YbCoZn.