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Title: Irreversibility Line Measurement and Vortex Dynamics in High Magnetic Fields in Ni- and Co-Doped Iron Pnictide Bulk Superconductors

Abstract

The de-pinning or irreversibility lines were determined by ac susceptibility, magnetization, radio-frequency proximity detector oscillator (PDO), and resistivity methods in Ba(Fe 0.92Co 0.08) 2As 2 ( T c = 23.2 K), Ba(Fe 0.95Ni 0.05) 2As 2 ( T c = 20.4 K), and Ba(Fe 0.94Ni 0.06) 2As 2 ( T c = 18.5 K) bulk superconductors in ac, dc, and pulsed magnetic fields up to 65 T. A new method of extracting the irreversibility fields from the radio-frequency proximity detector oscillator induction technique is described. Wide temperature broadening of the irreversibility lines, for any given combination of ac and dc fields, is dependent on the time frame of measurement. Increasing the magnetic field sweep rate (dH/dt) shifts the irreversibility lines to higher temperatures up to about dH/d t = 40,000 Oe/s; for higher dH/dt, there is little impact on the irreversibility line. There is an excellent data match between the irreversibility fields obtained from magnetization hysteresis loops, PDO, and ac susceptibility measurements, but not from resistivity measurements in these materials. Lower critical field vs. temperature phase diagrams are measured. Their very low values near 0 T indicate that these materials are in mixed state in nonzero magnetic fields, and yetmore » the strength of the vortex pinning enables very high irreversibility fields, as high as 51 T at 1.5 K for the Ba(Fe 0.92Co 0.08) 2As 2 polycrystalline sample, showing a promise for liquid helium temperature applications.« less

Authors:
 [1];  [2];  [2];  [3];  [3];  [3]
  1. Saint Louis Univ., MO (United States). Dept. of Physics
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States). National High Magnetic Field Lab. (MagLab)
  3. Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE; National Science Foundation (NSF)
OSTI Identifier:
1345157
Report Number(s):
LA-UR-16-24938
Journal ID: ISSN 1557-1939; TRN: US1701778
Grant/Contract Number:
AC52-06NA25396; DMR- 1006584; DMR-1306785; DMR-1157490
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Journal of Superconductivity and Novel Magnetism
Additional Journal Information:
Journal Volume: 29; Journal Issue: 11; Journal ID: ISSN 1557-1939
Publisher:
Springer
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; 36 MATERIALS SCIENCE; Superconductivity; Pnictides; Irreversibility; Magnetization; AC susceptibilityRadio frequency proximity detector oscillator

Citation Formats

Nikolo, Martin, Singleton, John, Zapf, Vivien S., Jiang, Jianyi, Weiss, Jeremy D., and Hellstrom, Eric E. Irreversibility Line Measurement and Vortex Dynamics in High Magnetic Fields in Ni- and Co-Doped Iron Pnictide Bulk Superconductors. United States: N. p., 2016. Web. doi:10.1007/s10948-016-3628-6.
Nikolo, Martin, Singleton, John, Zapf, Vivien S., Jiang, Jianyi, Weiss, Jeremy D., & Hellstrom, Eric E. Irreversibility Line Measurement and Vortex Dynamics in High Magnetic Fields in Ni- and Co-Doped Iron Pnictide Bulk Superconductors. United States. doi:10.1007/s10948-016-3628-6.
Nikolo, Martin, Singleton, John, Zapf, Vivien S., Jiang, Jianyi, Weiss, Jeremy D., and Hellstrom, Eric E. 2016. "Irreversibility Line Measurement and Vortex Dynamics in High Magnetic Fields in Ni- and Co-Doped Iron Pnictide Bulk Superconductors". United States. doi:10.1007/s10948-016-3628-6. https://www.osti.gov/servlets/purl/1345157.
@article{osti_1345157,
title = {Irreversibility Line Measurement and Vortex Dynamics in High Magnetic Fields in Ni- and Co-Doped Iron Pnictide Bulk Superconductors},
author = {Nikolo, Martin and Singleton, John and Zapf, Vivien S. and Jiang, Jianyi and Weiss, Jeremy D. and Hellstrom, Eric E.},
abstractNote = {The de-pinning or irreversibility lines were determined by ac susceptibility, magnetization, radio-frequency proximity detector oscillator (PDO), and resistivity methods in Ba(Fe0.92Co0.08)2As2 ( Tc = 23.2 K), Ba(Fe0.95Ni0.05)2As2 ( Tc = 20.4 K), and Ba(Fe0.94Ni0.06)2As2 ( Tc = 18.5 K) bulk superconductors in ac, dc, and pulsed magnetic fields up to 65 T. A new method of extracting the irreversibility fields from the radio-frequency proximity detector oscillator induction technique is described. Wide temperature broadening of the irreversibility lines, for any given combination of ac and dc fields, is dependent on the time frame of measurement. Increasing the magnetic field sweep rate (dH/dt) shifts the irreversibility lines to higher temperatures up to about dH/d t = 40,000 Oe/s; for higher dH/dt, there is little impact on the irreversibility line. There is an excellent data match between the irreversibility fields obtained from magnetization hysteresis loops, PDO, and ac susceptibility measurements, but not from resistivity measurements in these materials. Lower critical field vs. temperature phase diagrams are measured. Their very low values near 0 T indicate that these materials are in mixed state in nonzero magnetic fields, and yet the strength of the vortex pinning enables very high irreversibility fields, as high as 51 T at 1.5 K for the Ba(Fe0.92Co0.08)2As2 polycrystalline sample, showing a promise for liquid helium temperature applications.},
doi = {10.1007/s10948-016-3628-6},
journal = {Journal of Superconductivity and Novel Magnetism},
number = 11,
volume = 29,
place = {United States},
year = 2016,
month = 7
}

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  • Comprehensive study of upper critical and irreversibility magnetic fields in Ba(Fe 0.95Ni 0.05) 2As 2 (large grain and small grain samples or Ni5(SG), Ni5(LG)), Ba(Fe 0.94Ni 0.06) 2As 2 (Ni6), Ba(Fe 0.92Co 0.08) 2As 2 (Co8), and Ba(Fe 0.92Co 0.09) 2As 2 (Co9) polycrystalline bulk pnictide superconductors was made in pulsed fields of up to 65 T.
  • The magnetic irreversibility line (IL) has been measured as a function of magnetic field and frequency using an ac inductance technique in single crystals of YBaCuO and BiSrCaCuO and in consolidated YBaCuO fibers. The IL is defined as the temperature of the peak in {ital X}{double prime} as a function of magnetic field. Above the IL magnetic flux is mobile in the superconductor and the critical current {ital J}{sub {ital c}} is zero; below the IL flux is pinned and a {ital J}{sub {ital c}} can exist. Very small ({lt}1 K) shifts in the temperature of the peak in {italmore » X}{double prime} in YBaCuO crystals are seen in fields up to 400 Oe, and for frequencies up to 20 kHz. In contrast, crystals of BiSrCaCuO show shifts downward of the {ital X}{double prime} peak temperature of more than 40 K at 100 Hz, and in fields of 400 Oe. Intermediate behavior is seen for YBaCuO fibers. These data and particularly the frequency dependence of the IL are discussed in terms of flux creep/flux flow in these materials.« less
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  • We consider the magnetic-field dependence of the plasma resonance frequency in pristine and in irradiated Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} crystals near T{sub c}. At low magnetic fields we relate linear in field corrections to the plasma frequency to the average distance between the pancake vortices in the neighboring layers (wandering length). We calculate the wandering length in the case of thermal wiggling of vortex lines, taking into account both Josephson and magnetic interlayer coupling of pancakes. Analyzing experimental data, we found that (i) the wandering length becomes comparable with the London penetration depth near T{sub c} and (ii) atmore » small melting fields (<20 G) the wandering length does not change much at the melting transition. This shows existence of the line liquid phase in this field range. We also found that pinning by columnar defects affects weakly the field dependence of the plasma resonance frequency near T{sub c}. (c) 2000 The American Physical Society.« less