195Pt Knight shift (KS) measurements covering the superconducting multiple phases for major field (H) orientations have been carried out on the high-quality single crystal UPt3. For H > 5 kOe, the KS does not change below the superconducting transition temperature Tc down to 28 mK, regardless of major crystal orientations, which provides evidence that the odd-parity superconductivity with the parallel spin pairing is realized. By contrast, the KS decreases below Tc for Hb||b axis and Hb < 5 kOe and for Hc||c axis and Hc <.3 kOe, whereas the KS for HA||A axis is T independent across Tc down to Ha˜1.764 kOe. These novel findings entitle UPt3 as the first spin-triplet odd-parity superconductor including a nonunitary pairing characterized by the two-component d vector like db+idc at low T and low H.
ASJC Scopus subject areas
- Physics and Astronomy(all)