Abstract
An extended investigation of the electronic phase diagram of FeSe up to pressures of GPa by means of ac and dc magnetization, zero-field muon spin rotation (ZF SR), and neutron diffraction is presented. ZF SR indicates that at pressures GPa static magnetic order occurs in FeSe and occupies the full sample volume for GPa. ac magnetization measurements reveal that the superconducting volume fraction stays close to 100% up to the highest pressure investigated. In addition, above GPa both the superconducting transition temperature and the magnetic ordering temperature increase simultaneously, and both superconductivity and magnetism are stabilized with increasing pressure. Calculations indicate only one possible muon stopping site in FeSe, located on the line connecting the Se atoms along the direction. Different magnetic structures are proposed and checked by combining the muon stopping calculations with a symmetry analysis, leading to a similar structure as in the LaFeAsO family of Fe-based superconductors. Furthermore, it is shown that the magnetic moment is pressure dependent and with a rather small value of at GPa.
2 More- Received 12 December 2011
DOI:https://doi.org/10.1103/PhysRevB.85.064517
©2012 American Physical Society