Effect of magnetic field on magnetic excitation in heavy-fermion superconductors probed via neutron scattering

中性子散乱から見た重い電子系超伝導体における磁気励起の磁場効果

金子 耕士   ; Raymond, S.*; Hiess, A.*; Fk, B.*; Steffens, P.*; Lapertot, G.*; 摂待 力生*; 大貫 惇睦

Kaneko, Koji; Raymond, S.*; Hiess, A.*; Fk, B.*; Steffens, P.*; Lapertot, G.*; Settai, Rikio*; Onuki, Yoshichika

An interplay between magnetism and superconductivity is one of the main research subjects in the field of strongly correlated electron systems. Magnetic excitation of heavy-fermion superconductor CeCoIn (CCI5), which has the highest of 2.3 K among the Ce-based heavy-fermion superconductors, exhibits distinct change; a quasielastic magnetic response above turns into spin resonance below . Contrasting behaviour was obtained in non-centrosymmetric heavy-fermion superconductor CePtSi (CP3S) with = 2.2 K and 0.5 K. In CP3S, identical magnetic excitation spectra have been observed below and above . Instead, an external magnetic field induces a drastic enhancement of the antiferromagnetic moment. We will show our latest results on neutron scattering study under magnetic field to get insights into the nature of resonance in CCI5, and the origin of the antiferromagnetic moment enhancement in CP3S.