Inelastic neutron scattering from the antiferromagnetic (TN=9.7 K) heavy-fermion system U2Zn17 reveals magnetic fluctuations which are highly localized in reciprocal space and broad in frequency. At higher energies, the fluctuations persist almost unchanged to temperatures well above Tn. Analysis of the neutron and bulk susceptibility data in terms of Kondo-type single-ion response functions modified by Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between ions indicates that it is the temperature dependence anticipated theoretically of the effective RKKY coupling which drives the magnetic phase transition in U2Zn17. © 1987 The American Physical Society.

The current understanding of the superconductivity of heavy-electron uranium compounds is reviewed. Both the pairing and the mechanism appear to have been established as unusual in UPt3 and UBe13. Small-moment magnetic ordering is now known to coexist with superconductivity in URu2Si2 and UPt3. The understanding of the properties of UBe13 may be viewed as the central problem in heavy-electron physics. © 1988, Elsevier Science Publishers B.V.. All rights reserved.