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Title: Local structural disorder and superconductivity in K x Fe 2 - y Se 2

Abstract

We report significantly enhanced magnetic moment in K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) single crystals with sharp T c and bulk superconductivity obtained by postannealing and quenching process. There are two Fe sites in the K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) unit cell: Fe1, which has higher symmetry with longer average Fe-Se bond length, and Fe2, which has lower symmetry with shorter average Fe-Se bond length. Temperature-dependent x-ray absorption fine-structure (XAFS) analysis results on quenched and as-grown K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) crystals show that quenched K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) have increased average Fe-Se bond length and decreased static disorder. Our results indicate that nonzero population of Fe1 sites is the key structural parameter that governs the bulk superconductivity. We also show clear evidence that Fe1 sites carry higher magnetic moment than Fe2 sites.

Authors:
; ; ;
Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Emergent Superconductivity (CES)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1385609
DOE Contract Number:  
AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Physical Review. B, Condensed Matter and Materials Physics
Additional Journal Information:
Journal Volume: 85; Journal Issue: 22; Related Information: CES partners with Brookhaven National Laboratory (BNL); Argonne National Laboratory; University of Illinois, Urbana-Champaign; Los Alamos National Laboratory; Journal ID: ISSN 1098-0121
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; phonons, thermal conductivity, energy storage (including batteries and capacitors), superconductivity, defects, spin dynamics

Citation Formats

Ryu, Hyejin, Lei, Hechang, Frenkel, A. I., and Petrovic, C. Local structural disorder and superconductivity in K x Fe 2-y Se 2. United States: N. p., 2012. Web. doi:10.1103/PhysRevB.85.224515.
Ryu, Hyejin, Lei, Hechang, Frenkel, A. I., & Petrovic, C. Local structural disorder and superconductivity in K x Fe 2-y Se 2. United States. https://doi.org/10.1103/PhysRevB.85.224515
Ryu, Hyejin, Lei, Hechang, Frenkel, A. I., and Petrovic, C. 2012. "Local structural disorder and superconductivity in K x Fe 2-y Se 2". United States. https://doi.org/10.1103/PhysRevB.85.224515.
@article{osti_1385609,
title = {Local structural disorder and superconductivity in K x Fe 2-y Se 2},
author = {Ryu, Hyejin and Lei, Hechang and Frenkel, A. I. and Petrovic, C.},
abstractNote = {We report significantly enhanced magnetic moment in K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) single crystals with sharp T c and bulk superconductivity obtained by postannealing and quenching process. There are two Fe sites in the K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) unit cell: Fe1, which has higher symmetry with longer average Fe-Se bond length, and Fe2, which has lower symmetry with shorter average Fe-Se bond length. Temperature-dependent x-ray absorption fine-structure (XAFS) analysis results on quenched and as-grown K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) crystals show that quenched K 0.69 ( 2 ) Fe 1.45 ( 1 ) Se 2.00 ( 1 ) have increased average Fe-Se bond length and decreased static disorder. Our results indicate that nonzero population of Fe1 sites is the key structural parameter that governs the bulk superconductivity. We also show clear evidence that Fe1 sites carry higher magnetic moment than Fe2 sites.},
doi = {10.1103/PhysRevB.85.224515},
url = {https://www.osti.gov/biblio/1385609}, journal = {Physical Review. B, Condensed Matter and Materials Physics},
issn = {1098-0121},
number = 22,
volume = 85,
place = {United States},
year = {2012},
month = {6}
}

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