Increase of the critical current density of MgB2 superconducting bulk samples by means of methylene blue dye additions

Jean-Claude Grivel*, K. Rubešová

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

MgB2 bulk samples were made by means of reaction of elemental Mg and B powders with or without additions of methylene blue trihydrate, a carbon source, which melts at high temperature upon decomposition. The Tc of the MgB2 phase as well as its a-axis parameter were decreased as a result of carbon doping, whereas the c-axis parameter only shows a weak tendency for increasing. The critical current density of MgB2 was improved both in self-field and under applied magnetic field for T ≤ 25 K, the best results being obtained for 0.5–1.0 wt.% methylene blue trihydrate addition. Based on normalized flux pinning force (f(b)) versus reduced field (b) plots, it was found that the flux pinning mechanism at low reduced field is similar for all samples, with a behavior close to the predictions of the point pinning model. However, for b larger than 1, the behavior of f(b) is significantly altered in the methylene blue trihydrate added samples and tends towards the surface pinning model. Methylene blue trihydrate is an efficient carbon source and furthermore provides a liquid phase between 200 °C and 450 °C, which may have some influence on the critical current density improvements at low field.
Original languageEnglish
Article number1353506
JournalPhysica C: Superconductivity and its applications
Volume565
ISSN0921-4534
DOIs
Publication statusPublished - 2019

Keywords

  • MgB2
  • Doping
  • Carbon
  • Methylene blue
  • Dye

Cite this

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title = "Increase of the critical current density of MgB2 superconducting bulk samples by means of methylene blue dye additions",
abstract = "MgB2 bulk samples were made by means of reaction of elemental Mg and B powders with or without additions of methylene blue trihydrate, a carbon source, which melts at high temperature upon decomposition. The Tc of the MgB2 phase as well as its a-axis parameter were decreased as a result of carbon doping, whereas the c-axis parameter only shows a weak tendency for increasing. The critical current density of MgB2 was improved both in self-field and under applied magnetic field for T ≤ 25 K, the best results being obtained for 0.5–1.0 wt.{\%} methylene blue trihydrate addition. Based on normalized flux pinning force (f(b)) versus reduced field (b) plots, it was found that the flux pinning mechanism at low reduced field is similar for all samples, with a behavior close to the predictions of the point pinning model. However, for b larger than 1, the behavior of f(b) is significantly altered in the methylene blue trihydrate added samples and tends towards the surface pinning model. Methylene blue trihydrate is an efficient carbon source and furthermore provides a liquid phase between 200 °C and 450 °C, which may have some influence on the critical current density improvements at low field.",
keywords = "MgB2, Doping, Carbon, Methylene blue, Dye",
author = "Jean-Claude Grivel and K. Rubešov{\'a}",
year = "2019",
doi = "10.1016/j.physc.2019.1353506",
language = "English",
volume = "565",
journal = "Physica C: Superconductivity and its Applications",
issn = "0921-4534",
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Increase of the critical current density of MgB2 superconducting bulk samples by means of methylene blue dye additions. / Grivel, Jean-Claude; Rubešová, K.

In: Physica C: Superconductivity and its applications, Vol. 565, 1353506, 2019.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Increase of the critical current density of MgB2 superconducting bulk samples by means of methylene blue dye additions

AU - Grivel, Jean-Claude

AU - Rubešová, K.

PY - 2019

Y1 - 2019

N2 - MgB2 bulk samples were made by means of reaction of elemental Mg and B powders with or without additions of methylene blue trihydrate, a carbon source, which melts at high temperature upon decomposition. The Tc of the MgB2 phase as well as its a-axis parameter were decreased as a result of carbon doping, whereas the c-axis parameter only shows a weak tendency for increasing. The critical current density of MgB2 was improved both in self-field and under applied magnetic field for T ≤ 25 K, the best results being obtained for 0.5–1.0 wt.% methylene blue trihydrate addition. Based on normalized flux pinning force (f(b)) versus reduced field (b) plots, it was found that the flux pinning mechanism at low reduced field is similar for all samples, with a behavior close to the predictions of the point pinning model. However, for b larger than 1, the behavior of f(b) is significantly altered in the methylene blue trihydrate added samples and tends towards the surface pinning model. Methylene blue trihydrate is an efficient carbon source and furthermore provides a liquid phase between 200 °C and 450 °C, which may have some influence on the critical current density improvements at low field.

AB - MgB2 bulk samples were made by means of reaction of elemental Mg and B powders with or without additions of methylene blue trihydrate, a carbon source, which melts at high temperature upon decomposition. The Tc of the MgB2 phase as well as its a-axis parameter were decreased as a result of carbon doping, whereas the c-axis parameter only shows a weak tendency for increasing. The critical current density of MgB2 was improved both in self-field and under applied magnetic field for T ≤ 25 K, the best results being obtained for 0.5–1.0 wt.% methylene blue trihydrate addition. Based on normalized flux pinning force (f(b)) versus reduced field (b) plots, it was found that the flux pinning mechanism at low reduced field is similar for all samples, with a behavior close to the predictions of the point pinning model. However, for b larger than 1, the behavior of f(b) is significantly altered in the methylene blue trihydrate added samples and tends towards the surface pinning model. Methylene blue trihydrate is an efficient carbon source and furthermore provides a liquid phase between 200 °C and 450 °C, which may have some influence on the critical current density improvements at low field.

KW - MgB2

KW - Doping

KW - Carbon

KW - Methylene blue

KW - Dye

U2 - 10.1016/j.physc.2019.1353506

DO - 10.1016/j.physc.2019.1353506

M3 - Journal article

VL - 565

JO - Physica C: Superconductivity and its Applications

JF - Physica C: Superconductivity and its Applications

SN - 0921-4534

M1 - 1353506

ER -