Abstract
Elastic neutron diffraction measurements were performed on the quasi-two-dimensional heavy-fermion system , ranging from an incommensurate antiferromagnet for low Co composition to an unconventional superconductor on the Co-rich end of the phase diagram. We found that the superconductivity competes with the incommensurate antiferromagnetic (AFM) order characterized by with , while it coexists with the commensurate AFM order with . This is in sharp contrast to the system, where both the commensurate and incommensurate magnetic orders coexist with the superconductivity. These results reveal that particular areas on the Fermi surface nested by play an active role in forming the superconducting state in .
- Received 25 July 2007
DOI:https://doi.org/10.1103/PhysRevB.76.132507
©2007 American Physical Society