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Title: The preparation and phase diagrams of ( 7 Li 1-x Fe x OD)FeSe and (Li 1-x Fe x OH)FeSe superconductors

Abstract

We report the phase diagram for the superconducting system ( 7Li 1-xFe xOD)FeSe and contrast it with that of (Li 1-xFe xOH)FeSe both in single crystal and powder forms. Samples were prepared via hydrothermal methods and characterized by laboratory and synchrotron X-ray diffraction, high-resolution neutron powder diffraction (NPD), and high intensity NPD. We find a correlation between the tetragonality of the unit cell parameters and the critical temperature, Tc, which is indicative of the effects of charge doping on the lattice and formation of iron vacancies in the FeSe layer. We observe no appreciable isotope effect on the maximum Tc in substituting H by D. The NPD measurements definitively rule out an antiferromagnetic ordering in the non-superconducting (Li 1-xFe xOD)FeSe samples below 120 K, which has been reported in non-superconducting (Li 1-xFe xOH)FeSe. A likely explanation for the observed antiferromagnetic transition in (Li 1-xFe xOH)FeSe samples is the formation of impurities during their preparation such as Fe 3O 4 and Li xFeO 2, which express a charge ordering transition known as the Verwey transition near 120 K. The concentration of these oxide impurities is found to be dependent on the concentration of the lithium hydroxide reagent and the use ofmore » H 2O vs. D 2O as the solvent during synthesis. We also describe the reaction conditions that lead to some of our superconducting samples to exhibit ferromagnetism below T c.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
USDOE
OSTI Identifier:
1324785
Resource Type:
Journal Article
Journal Name:
Journal of Materials Chemistry. C
Additional Journal Information:
Journal Volume: 4; Journal Issue: 18; Journal ID: ISSN 2050-7526
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
ENGLISH
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY

Citation Formats

Zhou, Xiuquan, Borg, Christopher K. H., Lynn, Jeffrey W., Saha, Shanta R., Paglione, Johnpierre, and Rodriguez, Efrain E. The preparation and phase diagrams of (7 Li 1-x Fe x OD)FeSe and (Li 1-x Fe x OH)FeSe superconductors. United States: N. p., 2016. Web. doi:10.1039/C5TC04041H.
Zhou, Xiuquan, Borg, Christopher K. H., Lynn, Jeffrey W., Saha, Shanta R., Paglione, Johnpierre, & Rodriguez, Efrain E. The preparation and phase diagrams of (7 Li 1-x Fe x OD)FeSe and (Li 1-x Fe x OH)FeSe superconductors. United States. doi:10.1039/C5TC04041H.
Zhou, Xiuquan, Borg, Christopher K. H., Lynn, Jeffrey W., Saha, Shanta R., Paglione, Johnpierre, and Rodriguez, Efrain E. Fri . "The preparation and phase diagrams of (7 Li 1-x Fe x OD)FeSe and (Li 1-x Fe x OH)FeSe superconductors". United States. doi:10.1039/C5TC04041H.
@article{osti_1324785,
title = {The preparation and phase diagrams of (7 Li 1-x Fe x OD)FeSe and (Li 1-x Fe x OH)FeSe superconductors},
author = {Zhou, Xiuquan and Borg, Christopher K. H. and Lynn, Jeffrey W. and Saha, Shanta R. and Paglione, Johnpierre and Rodriguez, Efrain E.},
abstractNote = {We report the phase diagram for the superconducting system (7Li1-xFexOD)FeSe and contrast it with that of (Li1-xFexOH)FeSe both in single crystal and powder forms. Samples were prepared via hydrothermal methods and characterized by laboratory and synchrotron X-ray diffraction, high-resolution neutron powder diffraction (NPD), and high intensity NPD. We find a correlation between the tetragonality of the unit cell parameters and the critical temperature, Tc, which is indicative of the effects of charge doping on the lattice and formation of iron vacancies in the FeSe layer. We observe no appreciable isotope effect on the maximum Tc in substituting H by D. The NPD measurements definitively rule out an antiferromagnetic ordering in the non-superconducting (Li1-xFexOD)FeSe samples below 120 K, which has been reported in non-superconducting (Li1-xFexOH)FeSe. A likely explanation for the observed antiferromagnetic transition in (Li1-xFexOH)FeSe samples is the formation of impurities during their preparation such as Fe3O4 and LixFeO2, which express a charge ordering transition known as the Verwey transition near 120 K. The concentration of these oxide impurities is found to be dependent on the concentration of the lithium hydroxide reagent and the use of H2O vs. D2O as the solvent during synthesis. We also describe the reaction conditions that lead to some of our superconducting samples to exhibit ferromagnetism below Tc.},
doi = {10.1039/C5TC04041H},
journal = {Journal of Materials Chemistry. C},
issn = {2050-7526},
number = 18,
volume = 4,
place = {United States},
year = {2016},
month = {1}
}