We have studied electronic and magnetic properties of the K0.8Fe1.6Se2 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-Tc superconductivity in the title system. The results clearly underline the glassy nature of superconductivity in the electronically inhomogeneous K0.8Fe1.6Se2, similar to the superconductivity in granular phases.
Coexistence of different electronic phases in the K0.8Fe1.6Se2 superconductor: A bulk-sensitive hard x-ray spectroscopy study
MORETTI, MARCO;
2012-01-01
Abstract
We have studied electronic and magnetic properties of the K0.8Fe1.6Se2 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-Tc superconductivity in the title system. The results clearly underline the glassy nature of superconductivity in the electronically inhomogeneous K0.8Fe1.6Se2, similar to the superconductivity in granular phases.| File | Dimensione | Formato | |
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