NMR study of antiferromagnetic superconductor under high pressure and at Low temperatures

重费米子超导体中超导电性与磁性之间的相互作用是一个引人入胜的课题。特别是，铁磁或反铁磁自旋涨落的存在导致了系统中实现了具有非S波对称性的非传统库珀对态。我们研究了T=Co，Rh和Ir的CeTiN_5体系中的这些现象。通过核磁共振和核磁共振测量，证明该体系实现了d波超导电性。CeCoIn_5的核自旋-晶格驰豫速率随压力的变化关系表明，该体系在常压下正好位于量子临界点，并随着压力的增加而变为非磁性。高压下对Uru_2Si_2的核磁共振研究表明，在低温下实现了非磁性和反铁磁态的共存。随着压力的增加，反铁磁相的体积分数迅速增加。

The interplay between the superconductivity and the magnetism in the heavy fermion superconductors is a fascinating subject. In particular, the presence of ferromagnetic or antiferromagnetic spin fluctuations has led to the prediction that an unconventional Cooper pair state with non s-wave symmetry is realized in the system. We have study these phenomena in CeTIn_5 system with T=Co, Rh and Ir. We obtained the d-wave superconductivity is realized in the system from NMR and NQR measurements. The pressure dependence of the nuclear spin-lattice relaxation rate of ^<115>In in CeCoIn_5 has shown that the system locates just the Quantum critical point at ambient pressure and becomes non-magnetic with increasing pressure.The ^<29>Si NMR study of URu_2Si_2 under high pressure has shown that co-existence of the non-magnetic and the antiferromagnetic states is realized at low temperature. The volume fraction of antiferromagnetic phase increases rapidly with increasing pressure.