Magnetic order and fluctuations in superconductingUPt3

Abstract

Neutron diffraction shows that superconducting ${\mathrm{UPt}}_3$ can be an antiferromagnet with an ordered moment of (0.02±0.01)${\mathrm{\mu }}_{\mathrm{B}}$ and a Néel temperature (${\mathrm{T}}_{\mathrm{N}}$) of 5 K. The squared order parameter is linear function of temperature from ${\mathrm{T}}_{\mathrm{N}}$ to the superconducting transition temperature, ${\mathrm{T}}_{\mathrm{c}}$=0.5 K, below which it ceases to evolve. Inelastic neutron scattering demonstrates that the fluctuating moments are strongly correlated; the characteristic energy for fluctuations with wave vectors close to the ordering wave vector is 0.2 meV≊4${\mathrm{kT}}_{\mathrm{c}}$..AE