We have studied local magnetic moment and electronic phase separation in superconducting KxFe2-ySe2 by x-ray emission and absorption spectroscopy. Detailed temperature-dependent measurements at the Fe K-edge have revealed coexisting electronic phases and their correlation with the transport properties. By cooling down, the local magnetic moment of Fe shows a sharp drop across the superconducting transition temperature (T-c) and the coexisting phases exchange spectral weights with the low-spin state, gaining intensity at the expense of the higher-spin state. After annealing the sample across the iron-vacancy order temperature, the system does not recover the initial state and the spectral weight anomaly at T-c as well as superconductivity disappear. The results clearly underline that the coexistence of the low-spin and high-spin phases and the transitions between them provide unusual magnetic fluctuations and have a fundamental role in the superconducting mechanism of the electronically inhomogeneous KxFe2-ySe2 system.

Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide / L., Simonelli; T., Mizokawa; M., Moretti Sala; H., Takeya; Y., Mizuguchi; Y., Takano; G., Garbarino; G., Monaco; Saini, Naurang Lal. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 90:(2014). [10.1103/PhysRevB.90.214516]

Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide

SAINI, Naurang Lal
2014

Abstract

We have studied local magnetic moment and electronic phase separation in superconducting KxFe2-ySe2 by x-ray emission and absorption spectroscopy. Detailed temperature-dependent measurements at the Fe K-edge have revealed coexisting electronic phases and their correlation with the transport properties. By cooling down, the local magnetic moment of Fe shows a sharp drop across the superconducting transition temperature (T-c) and the coexisting phases exchange spectral weights with the low-spin state, gaining intensity at the expense of the higher-spin state. After annealing the sample across the iron-vacancy order temperature, the system does not recover the initial state and the spectral weight anomaly at T-c as well as superconductivity disappear. The results clearly underline that the coexistence of the low-spin and high-spin phases and the transitions between them provide unusual magnetic fluctuations and have a fundamental role in the superconducting mechanism of the electronically inhomogeneous KxFe2-ySe2 system.
2014
01 Pubblicazione su rivista::01a Articolo in rivista
Temperature dependence of iron local magnetic moment in phase-separated superconducting chalcogenide / L., Simonelli; T., Mizokawa; M., Moretti Sala; H., Takeya; Y., Mizuguchi; Y., Takano; G., Garbarino; G., Monaco; Saini, Naurang Lal. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 90:(2014). [10.1103/PhysRevB.90.214516]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/778020
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