Antiferromagnetic Spin Fluctuations in the Heavy-Fermion Superconductor UPt3

Abstract
The strength of the spin-fluctuation spectrum of UPt3 has been found, with neutron scattering, to decrease dramatically with temperature on approach to the superconducting transition. The spin fluctuations are antiferromagnetic. Their thermally activated intensity is consistent with the existence of a gaplike structure in the normal phase and shows that spin fluctuations take part in the formation of the superconducting state.