We have studied electronic and magnetic properties of the K 0.8Fe 1.6Se 2 superconductor by x-ray absorption and emission spectroscopy. Detailed temperature-dependent measurements along with a direct comparison with the binary FeSe system have revealed coexisting electronic phases: a majority phase with a high-spin 3 +Fe state and a minority phase with an intermediate-spin 2 +Fe state. The effect of high-temperature annealing suggests that the compressed phase with a lower-spin 2 +Fe state is directly related to the high-T c superconductivity in the title system. The results clearly underline the glassy nature of superconductivity in the electronically inhomogeneous K 0.8Fe 1.6Se 2, similar to the superconductivity in granular phases.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2012 Jun 7|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics