¹⁹⁵Pt Knight Shift in the Heavy Fermion Superconductor UPt₃

Abstract

We observed 195 Pt NMR in UPt 3 in both the normal and superconducting states, The spectrum has a large negative shift and is quite anisotropic. In 5 kOe, no changes in the negative shift were observed down to the temperature of 60 mK, where the system was in the superconducting state. This means that the conduction electron spin susceptibility does not decrease in the superconducting state. The result does not contradict the possibility of anisotropic p-wave superconductivity of UPt 3 .