Abstract
Neutron scattering is used to probe antiferromagnetic spin fluctuations in the -wave heavy fermion superconductor (). Superconductivity develops from a state with slow () commensurate [] antiferromagnetic spin fluctuations and nearly isotropic spin correlations. The characteristic wave vector in is the same as but differs from the incommensurate wave vector measured in antiferromagnetically ordered . A sharp spin resonance () at develops in the superconducting state removing spectral weight from low-energy transfers. The presence of a resonance peak is indicative of strong coupling between -electron magnetism and superconductivity and consistent with a -wave gap order parameter satisfying .
- Received 12 March 2007
DOI:https://doi.org/10.1103/PhysRevLett.100.087001
©2008 American Physical Society