Spin fluctuations in the heavy fermion superconductor UPd2Al3 studied by neutron inelastic scattering

We have found that there are two contributions to the dynamical response in UPd2Al3. The first is a heavily damped spin-wave: which has been observed previously. It shows no appreciable change on warming through T-c, but softens and becomes overdamped as T approaches T-N. The second is a quasielastic-like component that exists in the antiferromagnetically ordered state and is strongly localized around the ordered wavevector. As a function of temperature this component exhibits a minimum at the superconducting transition temperature T-c, and increases strongly below T-c. Its width in the momentum space at T = 0.5 K corresponds to a correlation length of similar to 50 Angstrom, which is close to the superconducting coherence length of similar to 85 Angstrom.