We report B 11 NMR measurements in noncentrosymmetric superconductors Mg9.3 Ir19 B16.7 (Tc =5.8 K) and Mg10.5 Ir19 B17.1 (Tc =4.8 K). The spin-lattice relaxation rate and the Knight shift indicate that the Cooper pairs are predominantly in the spin-singlet state with an isotropic gap. However, Mg10.5 Ir19 B17.1 is found to have more defects and the spin susceptibility remains finite even in the zero-temperature limit. We interpret this result as that the defects enhance the spin-orbit coupling and bring about more spin-triplet component.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - Aug 11 2009|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics