Nonunitary Spin-Triplet Superconductivity inUPt3: Evidence fromP195

Abstract

195 Pt Knight shift (KS) measurements covering the superconducting multiple phases for major field (H) orientations have been carried out on the high-quality single crystal UPt 3 . For H . 5 kOe, the KS does not change below the superconducting transition temperature T c 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 T c for H b k b axis and H b , 5 kOe and for H c k c axis and H c , 2.3 kOe, whereas the KS for H a k a axis is T independent across T c down to H a ϳ 1.764 kOe. These novel findings entitle UPt 3 as the first spin-triplet oddparity superconductor including a nonunitary pairing characterized by the two-component d vector like d b 1 id c at low T and low H. [S0031-9007(98)

Possible triplet superconductivity in the quasi-one-dimensional conductor Li0.9Mo6O17

“…Triplet superconductivity is a rather unusual phenomenon. In our opinion, it has been firmly established in the heavy fermion superconductor UPt 3 [21] and most likely exists in the Sr 2 RuO 4 [22,23] and ferromagnetic superconductors [24].…”

Tunnelling current in triplet superconductors with horizontal lines of nodes

“…Knight-shift measurements show that the parity of the pairing function of UPt 3 is odd and a spin triplet pairing state is realized [6]. Muon spin rotation experiments show that the time reversal symmetry is broken bellow T c2 for the superconductor UPt 3 [7].…”

Effects of superconducting gap anisotropy on the flux flow resistivity inY(Ni1−xPt

“…The enhancement of ρ f has actually been observed [8,9]. However, since UPt 3 is a complicated odd-parity superconductor [10], it should be noted that many factors other than gap anisotropy can contribute to ρ f . In fact, Lütke-Entrup et al attributed the origin of the ρ f enhancement to the unconventional vortex core structure which is brought by the two-component order parameter [9].…”