Effects of Magnetic Order on the Upper Critical Field of UPt${}_3$

Abstract

I present a Ginzburg-Landau theory for hexagonal oscillations of the upper critical field of UPt${}_3$ near $T_c$. The model is based on a $2D$ representation for the superconducting order parameter, $\vec{\eta }=({\eta }_1,{\eta }_2)$, coupled to an in-plane AFM order parameter, ${\vec{m}}_s$. Hexagonal anisotropy of $H_{c2}$ arises from the weak in-plane anisotropy energy of the AFM state and the coupling of the superconducting order parameter to the staggered field. The model explains the important features of the observed hexagonal anisotropy [N. Keller, {\it et al.}, Phys. Rev. Lett. {\bf 73}, 2364 (1994).] including: (i) the small magnitude, (ii) persistence of the oscillations for $T\to T_c$, and (iii) the change in sign of the oscillations for $T>T^{\ast }$ and $T<T^{\ast }$ (the temperature at the tetracritical point). I also show that there is a low-field crossover (observable only very near $T_c$) below which the oscillations should vanish.

9 pages in a RevTex (3.0) file plus 2 postscript figures (uuencoded). Submitted to Physical Review B (December 20, 1994).

References in corpus (1)

• The Order Parameter for the Superconducting Phases of UPt${}_3$

Cited by in corpus (10)

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• Violation of Emergent Rotational Symmetry in the Hexagonal Kagome Superconductor CsV3Sb5
• Upper critical field in a trigonal unconventional superconductor UPt_3
• Magnetic Field Effects on Neutron Diffraction in the Antiferromagnetic Phase of $UP{t}_3$
• Antiferromagnetic Domains and Superconductivity in UPt3
• Reply to ``Comment on `Magnetic field effects on neutron diffraction in the antiferromagnetic phase of $UP{t}_3$'''
• Antiferromagnetism and Superconductivity in UPt_3