Abstract
Neutron scattering demonstrates the coexistence of antiferromagnetic order and superconductivity below 1 K in the heavy-electron system . It is found that the upper (17.5 K) transition is to an antiferromagnetic phase with a (100) modulation wave vector and spins along the tetragonal c-axis. The ordered moment is unusually small, (0.03±0.01). However, spin waves develop from damped, finite-gap excitations above , and they are intense, propagating, and longitudinal with a zone centre gap of 1.8 meV.
- Received 9 October 1986
DOI:https://doi.org/10.1103/PhysRevLett.58.1467
©1987 American Physical Society