Abstract
Inelastic neutron-scattering measurements of under applied hydrostatic pressure show that the antiferromagnetic spin fluctuations observed in the ambient pressure, paramagnetic, and tetragonal phase are strongly suppressed, if not absent, in the collapsed tetragonal phase. These results are consistent with a quenched Fe moment in the phase and the strong decrease in resistivity observed upon crossing the boundary from the to phases. The suppression or absence of static antiferromagnetic order and dynamic spin fluctuations in the nonsuperconducting phase supports the notion of a coupling between spin fluctuations and superconductivity in the iron arsenides.
- Received 20 January 2009
DOI:https://doi.org/10.1103/PhysRevB.79.060510
©2009 American Physical Society