¹⁹⁵pt Knight shift study of single crystal UPt₃- evidence for odd-parity pairing

The ¹⁹⁵pt Knight shift of the high quality single crystal UPt₃ measured down to T=28 mK have revealed no change across T_c regardless of the applied field directions and of the superconducting multiphases. An estimation of the spin part from the T linear specific heat has ensured no variation of the dominant spin part of the measured Knight shift below Te as well as its estimation by the subtraction of the Van Vleck part from the T dependence of the Knight shift in the high T region reported in the previous paper. It is reinforced that UPt₃ is the odd-parity superconductor with equal spin pairing and the pinning of the order parameter does not take place, suggesting the spin-orbit coupling for the pairing interaction to be not so strong.