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Title: Effects of electron irradiation on resistivity and London penetration depth of Ba1-xKxFe2As2 (x <= 0.34) iron-pnictide superconductor

Abstract

Irradiation with 2.5 MeV electrons at doses up to 5.2×1019 electrons/cm2 was used to introduce pointlike defects in single crystals of Ba1-xKxFe2As2 with x=0.19 (Tc=14K),0.26 (Tc=32K), 0.32 (Tc=37K), and 0.34 (Tc=39K) to study the superconducting gap structure by probing the effect of nonmagnetic scattering on electrical resistivity ρ(T) and London penetration depth λ(T). For all compositions, the irradiation suppressed the superconducting transition temperature Tc and increased resistivity. The low-temperature behavior of λ(T) is best described by the power-law function, Δλ(T)=A(T/Tc)n. While substantial suppression of Tc supports s± pairing, in samples close to the optimal doping, x=0.26, 0.32, and 0.34, the exponent n remained high (n≥3), indicating almost exponential attenuation and thus a robust full superconducting gap. For the x=0.19 composition, which exhibits coexistence of superconductivity and long-range magnetism, the suppression of Tc was much more rapid, and the exponent n decreased toward the s± dirty limit of n=2. In this sample, the irradiation also suppressed the temperature of structural/magnetic transition Tsm from 103 to 98 K, consistent with the itinerant nature of the long-range magnetic order. Our results suggest that underdoped compositions, especially in the coexisting regime, are most susceptible to nonmagnetic scattering and imply that in multiband Ba1-xKxFe2As2 superconductors,more » the ratio of the interband to intraband pairing strength, as well as the related gap anisotropy, increases upon the departure from the optimal doping.« less

Authors:
 [1];  [2];  [1];  [1];  [1];  [1];  [3];  [3];  [1]
  1. Ames Laboratory
  2. Laboratoire des Solides Irradies
  3. Nanjing University
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
1166894
Report Number(s):
IS-J 8480
Journal ID: ISSN 1098-0121; PRBMDO; ArticleNumber: 104514
DOE Contract Number:  
DE-AC02-07CH11358
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. B, Condensed Matter and Materials Physics; Journal Volume: 90; Journal Issue: 10
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE

Citation Formats

Cho, K, Konczykowski, M, Murphy, Jason, Kim, H, Tanatar, Makariy A, Straszheim, Warren E, Shen, B, Wen, H H, and Prozorov, Ruslan. Effects of electron irradiation on resistivity and London penetration depth of Ba1-xKxFe2As2 (x <= 0.34) iron-pnictide superconductor. United States: N. p., 2014. Web. doi:10.1103/PhysRevB.90.104514.
Cho, K, Konczykowski, M, Murphy, Jason, Kim, H, Tanatar, Makariy A, Straszheim, Warren E, Shen, B, Wen, H H, & Prozorov, Ruslan. Effects of electron irradiation on resistivity and London penetration depth of Ba1-xKxFe2As2 (x <= 0.34) iron-pnictide superconductor. United States. doi:10.1103/PhysRevB.90.104514.
Cho, K, Konczykowski, M, Murphy, Jason, Kim, H, Tanatar, Makariy A, Straszheim, Warren E, Shen, B, Wen, H H, and Prozorov, Ruslan. Mon . "Effects of electron irradiation on resistivity and London penetration depth of Ba1-xKxFe2As2 (x <= 0.34) iron-pnictide superconductor". United States. doi:10.1103/PhysRevB.90.104514.
@article{osti_1166894,
title = {Effects of electron irradiation on resistivity and London penetration depth of Ba1-xKxFe2As2 (x <= 0.34) iron-pnictide superconductor},
author = {Cho, K and Konczykowski, M and Murphy, Jason and Kim, H and Tanatar, Makariy A and Straszheim, Warren E and Shen, B and Wen, H H and Prozorov, Ruslan},
abstractNote = {Irradiation with 2.5 MeV electrons at doses up to 5.2×1019 electrons/cm2 was used to introduce pointlike defects in single crystals of Ba1-xKxFe2As2 with x=0.19 (Tc=14K),0.26 (Tc=32K), 0.32 (Tc=37K), and 0.34 (Tc=39K) to study the superconducting gap structure by probing the effect of nonmagnetic scattering on electrical resistivity ρ(T) and London penetration depth λ(T). For all compositions, the irradiation suppressed the superconducting transition temperature Tc and increased resistivity. The low-temperature behavior of λ(T) is best described by the power-law function, Δλ(T)=A(T/Tc)n. While substantial suppression of Tc supports s± pairing, in samples close to the optimal doping, x=0.26, 0.32, and 0.34, the exponent n remained high (n≥3), indicating almost exponential attenuation and thus a robust full superconducting gap. For the x=0.19 composition, which exhibits coexistence of superconductivity and long-range magnetism, the suppression of Tc was much more rapid, and the exponent n decreased toward the s± dirty limit of n=2. In this sample, the irradiation also suppressed the temperature of structural/magnetic transition Tsm from 103 to 98 K, consistent with the itinerant nature of the long-range magnetic order. Our results suggest that underdoped compositions, especially in the coexisting regime, are most susceptible to nonmagnetic scattering and imply that in multiband Ba1-xKxFe2As2 superconductors, the ratio of the interband to intraband pairing strength, as well as the related gap anisotropy, increases upon the departure from the optimal doping.},
doi = {10.1103/PhysRevB.90.104514},
journal = {Physical Review. B, Condensed Matter and Materials Physics},
number = 10,
volume = 90,
place = {United States},
year = {Mon Sep 01 00:00:00 EDT 2014},
month = {Mon Sep 01 00:00:00 EDT 2014}
}