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Title: Critical fields of superconductors with magnetic impurities

Abstract

The upper critical field Hc2, the field Hc3 for nucleation of the surface superconductivity, and the thermodynamic field Hc are evaluated within the weak-coupling theory for the isotropic s-wave case with arbitrary transport, and pair-breaking scattering. In this study, we find that, for the standard geometry of a half-space sample in a magnetic field parallel to the surface, the ratio $$\mathscr{R}$$=Hc3/Hc2 is within the window 1.55≲$$\mathscr{R}$$≲2.34 , regardless of temperature or the scattering type. While the nonmagnetic impurities tend to flatten the $$\mathscr{R}$$($$\mathrm{T}$$) variation, magnetic scattering merely shifts the maximum of $$\mathscr{R}$$($$\mathrm{T}$$) to lower temperatures. Surprisingly, while reducing the transition temperature, magnetic scattering has a milder impact on $$\mathscr{R}$$ than nonmagnetic scattering. The surface superconductivity is quite robust; in fact, the ratio $$\mathscr{R}$$≈1.7 even in the gapless state. We used Eilenberger's energy functional to evaluate the condensation energy Fc and the thermodynamic critical field Hc for any temperature and scattering parameters. By comparing Hc2 and Hc, we find that, unlike transport scattering, the pair-breaking pushes materials toward type-I behavior. Furthermore, we find a peculiar behavior of Fc as a function of the pair-breaking scattering parameter at the low-$$\mathrm{T}$$ transition from gapped to gapless phases, which has recently been associated with the topological transition in the superconducting density of states.

Authors:
ORCiD logo [1]; ORCiD logo [1]
  1. Ames Lab., Ames, IA (United States); Iowa State Univ., Ames, IA (United States)
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division
OSTI Identifier:
1881869
Report Number(s):
IS-J 10,870
Journal ID: ISSN 2469-9950; TRN: US2307872
Grant/Contract Number:  
AC02-07CH11358; AC02-07CH11359
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review. B
Additional Journal Information:
Journal Volume: 106; Journal Issue: 5; Journal ID: ISSN 2469-9950
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; critical field; impurities in superconductors; superconducting phase transition; superconductors

Citation Formats

Kogan, V. G., and Prozorov, R. Critical fields of superconductors with magnetic impurities. United States: N. p., 2022. Web. doi:10.1103/physrevb.106.054505.
Kogan, V. G., & Prozorov, R. Critical fields of superconductors with magnetic impurities. United States. https://doi.org/10.1103/physrevb.106.054505
Kogan, V. G., and Prozorov, R. Thu . "Critical fields of superconductors with magnetic impurities". United States. https://doi.org/10.1103/physrevb.106.054505. https://www.osti.gov/servlets/purl/1881869.
@article{osti_1881869,
title = {Critical fields of superconductors with magnetic impurities},
author = {Kogan, V. G. and Prozorov, R.},
abstractNote = {The upper critical field Hc2, the field Hc3 for nucleation of the surface superconductivity, and the thermodynamic field Hc are evaluated within the weak-coupling theory for the isotropic s-wave case with arbitrary transport, and pair-breaking scattering. In this study, we find that, for the standard geometry of a half-space sample in a magnetic field parallel to the surface, the ratio $\mathscr{R}$=Hc3/Hc2 is within the window 1.55≲$\mathscr{R}$≲2.34 , regardless of temperature or the scattering type. While the nonmagnetic impurities tend to flatten the $\mathscr{R}$($\mathrm{T}$) variation, magnetic scattering merely shifts the maximum of $\mathscr{R}$($\mathrm{T}$) to lower temperatures. Surprisingly, while reducing the transition temperature, magnetic scattering has a milder impact on $\mathscr{R}$ than nonmagnetic scattering. The surface superconductivity is quite robust; in fact, the ratio $\mathscr{R}$≈1.7 even in the gapless state. We used Eilenberger's energy functional to evaluate the condensation energy Fc and the thermodynamic critical field Hc for any temperature and scattering parameters. By comparing Hc2 and Hc, we find that, unlike transport scattering, the pair-breaking pushes materials toward type-I behavior. Furthermore, we find a peculiar behavior of Fc as a function of the pair-breaking scattering parameter at the low-$\mathrm{T}$ transition from gapped to gapless phases, which has recently been associated with the topological transition in the superconducting density of states.},
doi = {10.1103/physrevb.106.054505},
journal = {Physical Review. B},
number = 5,
volume = 106,
place = {United States},
year = {Thu Aug 04 00:00:00 EDT 2022},
month = {Thu Aug 04 00:00:00 EDT 2022}
}

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