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Persistent Fe Moments in the Normal-State Collapsed-Tetragonal Phase of the Pressure-induced Superconductor Ca0.67Sr0.33Fe2As2
Published
Author(s)
J.R. Jeffries, Nicholas Butch, M.J. Lipp, J.A. Bradley, K. Kirshenbaum, Shanta Saha, J. Paglione, C. Kenny-Benson, Y. Xiao, P. Chow, W. J. Evans
Abstract
Using non-resonant Fe Κ}β x-ray emission spectroscopy, we reveal that Sr-doping of CaFe2As2 decouples the Fe moment from the volume collapse transition, yielding a collapsed-tetragonal, para-magnetic normal state out of which superconductivity develops. X-ray diffraction measurements implicate the c-axis lattice parameter as the controlling criterion for the Fe moment, promoting a generic description for the appearance of pressure-induced superconductivity in the alkaline-earth-based 122 ferropnictides (AFe2As2). The evolution of Tc with pressure lends support to theories for superconductivity involving unconventional pairing mediated by magnetic fluctuations.
Jeffries, J.
, Butch, N.
, Lipp, M.
, Bradley, J.
, Kirshenbaum, K.
, Saha, S.
, Paglione, J.
, Kenny-Benson, C.
, Xiao, Y.
, Chow, P.
and Evans, W.
(2014),
Persistent Fe Moments in the Normal-State Collapsed-Tetragonal Phase of the Pressure-induced Superconductor Ca<sub>0.67</sub>Sr<sub>0.33</sub>Fe<sub>2</sub>As<sub>2</sub>, Physical Review B, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=915046
(Accessed October 16, 2025)