Evidence for weak spin–orbit interaction experienced by cooper pairs in the spin-triplet superconductor UPT3: 195PT-NMR study

Taisuke Aoyama, Hisashi Kotegawa, Noriaki Kimura, Etsuji Yamamoto, Yoshinori Haga, Yoshichika Ōnuki, Hideki Tou

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Abstract

195Pt-NMR measurements for H ∥ c in the vicinity of the upper critical field Hc2 kc have been carried out on the heavy-fermion superconductor UPt3. The195Pt NMR line does not change its profile or its resonance frequency across the superconducting transition temperature Tc. This behavior is consistent with the previous experimental results showing that the spin susceptibility remains unchanged across Tc in the superconducting C phase [H. Tou et al., Phys. Rev. Lett. 77, 1374 (1996) and Gannon et al., Phys. Rev. B 96, 041111(R) (2017)]. The lack of the first-order phase transition across Tc(H) strongly indicates that the Pauli limiting effect inherent in the ∣Sz = 0〉 component does not occur near Hc2 kc. This experimental finding is supported by the analysis of the Pauli limiting field based on the superconducting thermodynamics. We also discuss the field dependence of the quasiparticle spin susceptibility in the superconducting state. The field dependence of the Knight shift cannot be explained by the behavior of the spin-triplet superconducting state having ∣Sz = 0〉. It is strongly indicated that the d-vector rotates freely above 5 kOe and that the spin–orbit interaction experienced by the Cooper pairs is weak in UPt3

Original languageEnglish
Article number064706
Journaljournal of the physical society of japan
Volume88
Issue number6
DOIs
Publication statusPublished - 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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