Abstract
Antiferromagnetic ordering and structural phase transition have been investigated via comprehensive neutron and x-ray diffraction on Sn-flux-grown single crystals, the family of FeAs-based high- superconductor compounds. The incorporation of Sn in the lattice resulted to an average composition of . A tetragonal-to-orthorhombic structural phase transition and a three-dimensional long-range antiferromagnetic ordering of the iron magnetic moment, with a unique magnetic propagation wave vector have been found to take place at . The magnetic moments of iron are aligned along the longer axis in the low-temperature orthorhombic phase ( with ). Our results thus demonstrate that the magnetic structure of the Sn-flux-grown single crystal is the same as those in the polycrystalline samples and in other iron pnictides compounds. We argue that the Sn incorporation in the lattice is responsible for a smaller orthorhombic splitting and lower Néel temperature observed in the experiments.
- Received 8 August 2008
DOI:https://doi.org/10.1103/PhysRevB.79.064504
©2009 American Physical Society