Induced-moment magnetic form factor of the heavy fermion superconductors UPt(3), UBe(13), and CeCu(2)Si(2).

Polarized neutron scattering techniques have been used to study the spatial distribution and temperature-dependence of the magnetization induced in single crystals of UPt(3), UBe(13), and CeCu(2)Si(2) by an externally applied magnetic field. We find that (a) the induced magnetization in the normal low temperature state is predominantly of f-electronic character and that (b) the generalized electronic susceptibility X(Q (vector),0) (where Q(vector) is a reciprocal lattice vector), obtained by measurements with H H(c2), is temperature-independent between 4.2K down to approximately 100mK. This result implies that either the superconductivity in these compounds is unconventional or that there is significant spin-orbit scattering by impurities in the samples. This latter possibility notwithstanding, the experimental results impose severe restrictions on the possible superconducting states of these systems.