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Title: Study of the second magnetization peak and the pinning behaviour in Ba(Fe 0.935 Co 0.065 ) 2 As 2 pnictide superconductor

Abstract

Isothermal magnetic field dependence of magnetization and magnetic relaxation measurements were performed for the $$H\parallel {\rm{c}}$$ axis on a single crystal of Ba(Fe 0.935 Co 0.065) 2As 2 pnictide superconductor having T c = 21.7 K. The second magnetization peak (SMP) for each isothermal M(H) was observed in a wide temperature range from T c to the lowest temperature of measurement (2 K). The magnetic field dependence of relaxation rate R(H), showed a peak (H spt) between H on (onset of SMP in M(H)) and H p (peak field of SMP in M(H)), which is likely to be related to a vortex-lattice structural phase transition, as suggested in the literature for a similar sample. In addition, the magnetic relaxation measured for magnetic fields near H spt showed some noise, which might be the signature of the structural phase transition of the vortex lattice. Analysis of the magnetic relaxation data using Maley's criterion and the collective pinning theory suggested that the SMP in the sample was due to the collective (elastic) to plastic creep crossover, which was also accompanied by a rhombic to square vortex lattice phase transition. The analysis of the pinning force density suggested a single dominating pinning mechanism in the sample, which did not showing the usual $$\delta {l}$$ and $$\delta {T}_{{\rm{c}}}$$ nature of pinning. Furthermore, the critical current density (J c), estimated using the Bean critical state model, was found to be 5 × 10 5 A cm - 2 at 2 K in the zero magnetic field limit. Surprisingly, the maximum of the pinning force density was not responsible for the maximum value of the critical current density in the sample.

Authors:
ORCiD logo [1];  [2];  [3];  [2]; ORCiD logo [4];  [1]
  1. Federal Univ. of Rio de Janeiro (Brazil). Inst. of Physics
  2. Univ. of Santiago (Spain). Dept. of Particle Physics
  3. National Inst. of Metrology Standardization and Industrial Quality, Rio de Janeiro (Brazil)
  4. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1414684
DOE Contract Number:  
AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Superconductor Science and Technology
Additional Journal Information:
Journal Volume: 30; Journal Issue: 12; Journal ID: ISSN 0953-2048
Publisher:
IOP Publishing
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; iron-based superconductors; single crystal; second magnetization peak; magnetic relaxation; critical current density; unconventional pinning

Citation Formats

Sundar, Shyam, Mosqueira, J., Alvarenga, A. D., Sóñora, D., Sefat, A. S., and Salem-Sugui, S. Study of the second magnetization peak and the pinning behaviour in Ba(Fe 0.935 Co 0.065 ) 2 As 2 pnictide superconductor. United States: N. p., 2017. Web. doi:10.1088/1361-6668/aa90b4.
Sundar, Shyam, Mosqueira, J., Alvarenga, A. D., Sóñora, D., Sefat, A. S., & Salem-Sugui, S. Study of the second magnetization peak and the pinning behaviour in Ba(Fe 0.935 Co 0.065 ) 2 As 2 pnictide superconductor. United States. doi:10.1088/1361-6668/aa90b4.
Sundar, Shyam, Mosqueira, J., Alvarenga, A. D., Sóñora, D., Sefat, A. S., and Salem-Sugui, S. Wed . "Study of the second magnetization peak and the pinning behaviour in Ba(Fe 0.935 Co 0.065 ) 2 As 2 pnictide superconductor". United States. doi:10.1088/1361-6668/aa90b4.
@article{osti_1414684,
title = {Study of the second magnetization peak and the pinning behaviour in Ba(Fe 0.935 Co 0.065 ) 2 As 2 pnictide superconductor},
author = {Sundar, Shyam and Mosqueira, J. and Alvarenga, A. D. and Sóñora, D. and Sefat, A. S. and Salem-Sugui, S.},
abstractNote = {Isothermal magnetic field dependence of magnetization and magnetic relaxation measurements were performed for the $H\parallel {\rm{c}}$ axis on a single crystal of Ba(Fe0.935 Co0.065)2As2 pnictide superconductor having T c = 21.7 K. The second magnetization peak (SMP) for each isothermal M(H) was observed in a wide temperature range from T c to the lowest temperature of measurement (2 K). The magnetic field dependence of relaxation rate R(H), showed a peak (H spt) between H on (onset of SMP in M(H)) and H p (peak field of SMP in M(H)), which is likely to be related to a vortex-lattice structural phase transition, as suggested in the literature for a similar sample. In addition, the magnetic relaxation measured for magnetic fields near H spt showed some noise, which might be the signature of the structural phase transition of the vortex lattice. Analysis of the magnetic relaxation data using Maley's criterion and the collective pinning theory suggested that the SMP in the sample was due to the collective (elastic) to plastic creep crossover, which was also accompanied by a rhombic to square vortex lattice phase transition. The analysis of the pinning force density suggested a single dominating pinning mechanism in the sample, which did not showing the usual $\delta {l}$ and $\delta {T}_{{\rm{c}}}$ nature of pinning. Furthermore, the critical current density (J c), estimated using the Bean critical state model, was found to be 5 × 105 A cm- 2 at 2 K in the zero magnetic field limit. Surprisingly, the maximum of the pinning force density was not responsible for the maximum value of the critical current density in the sample.},
doi = {10.1088/1361-6668/aa90b4},
journal = {Superconductor Science and Technology},
issn = {0953-2048},
number = 12,
volume = 30,
place = {United States},
year = {2017},
month = {11}
}