Abstract
We studied phase separation in the single-crystalline antiferromagnetic superconductor (RFS) using a combination of scattering-type scanning near-field optical microscopy and low-energy muon spin rotation (LE-). We demonstrate that the antiferromagnetic and superconducting phases segregate into nanometer-thick layers perpendicular to the iron-selenide planes, while the characteristic in-plane size of the metallic domains reaches . By means of LE- we further show that in a 40-nm thick surface layer the ordered antiferromagnetic moment is drastically reduced, while the volume fraction of the paramagnetic phase is significantly enhanced over its bulk value. Self-organization into a quasiregular heterostructure indicates an intimate connection between the modulated superconducting and antiferromagnetic phases.
- Received 23 February 2012
DOI:https://doi.org/10.1103/PhysRevLett.109.017003
© 2012 American Physical Society