Abstract
The new -Fe(Te,Se) superconductors share the common iron building block and ferminology with the LaFeAsO and families of superconductors. In contrast with the predicted commensurate spin-density-wave order at the nesting wave vector (, 0), a completely different magnetic order with a composition tunable propagation vector (, ) was determined for the parent compound in this powder and single-crystal neutron diffraction study. The new antiferromagnetic order survives as a short-range one even in the highest sample. An alternative to the prevailing nesting Fermi surface mechanism is required to understand the latest family of ferrous superconductors.
- Received 29 September 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.247001
©2009 American Physical Society