Beneficial Impact of Excess Mg on Flux Pinning in Bulk MgB2 Synthesized with Ag Addition and Carbon Encapsulated Boron

Research output: Contribution to journalArticle

Abstract

Silver addition has been known to improve mechanical and superconducting performance of bulk magnesium boride (MgB2) superconductor synthesized via solid state sintering. While formation of pinning phases and impurities such as Ag–Mg phases and MgO, respectively, responsible for high performance, part of the Mg in initial mixture will be expected to be consumed by silver. In this work, the authors add varied amounts of Mg systematically such as x: 2 (while x = 1.05, 1.075, 1.1, 1.125, 1.15) ratio of Mg:B instead of usual stoichiometric ratio of 1:2. To obtain high superconducting properties, the authors use carbon encapsulated boron (1.5% carbon) along with 4 wt% Ag. X-ray diffraction analysis shows the presence of Ag–Mg phases and minute amount of MgO. Superconducting quantum interference device (SQUID) measurements indicate that high irreversibility field (4.76 T) and large Jc of 520, 440, and 347 kA cm−2 at 10, 15, and 20 K, respectively, at self-field was exhibited in sample with x = 1.075. Flux pinning force studies are done to analyze the effect of secondary phases formed. All results analyzed explain the improved critical current performance based on nanometer-sized Ag–Mg particles in the final product.

Original languageEnglish
Article number1900497
JournalAdvanced Engineering Materials
DOIs
Publication statusPublished - 2019 Jan 1

Fingerprint

Flux pinning
Boron
flux pinning
Silver
boron
Carbon
Borides
carbon
Critical currents
SQUIDs
silver
X ray diffraction analysis
Superconducting materials
Magnesium
borides
Sintering
Impurities
magnesium
critical current
sintering

Keywords

  • Ag added bulk MgB
  • carbon encapsulated boron
  • excess Mg
  • flux pinning

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics

Cite this

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title = "Beneficial Impact of Excess Mg on Flux Pinning in Bulk MgB2 Synthesized with Ag Addition and Carbon Encapsulated Boron",
abstract = "Silver addition has been known to improve mechanical and superconducting performance of bulk magnesium boride (MgB2) superconductor synthesized via solid state sintering. While formation of pinning phases and impurities such as Ag–Mg phases and MgO, respectively, responsible for high performance, part of the Mg in initial mixture will be expected to be consumed by silver. In this work, the authors add varied amounts of Mg systematically such as x: 2 (while x = 1.05, 1.075, 1.1, 1.125, 1.15) ratio of Mg:B instead of usual stoichiometric ratio of 1:2. To obtain high superconducting properties, the authors use carbon encapsulated boron (1.5{\%} carbon) along with 4 wt{\%} Ag. X-ray diffraction analysis shows the presence of Ag–Mg phases and minute amount of MgO. Superconducting quantum interference device (SQUID) measurements indicate that high irreversibility field (4.76 T) and large Jc of 520, 440, and 347 kA cm−2 at 10, 15, and 20 K, respectively, at self-field was exhibited in sample with x = 1.075. Flux pinning force studies are done to analyze the effect of secondary phases formed. All results analyzed explain the improved critical current performance based on nanometer-sized Ag–Mg particles in the final product.",
keywords = "Ag added bulk MgB, carbon encapsulated boron, excess Mg, flux pinning",
author = "Arvapalli, {Sai S.} and Muralidhar Miryala and Masato Murakami",
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AU - Arvapalli, Sai S.

AU - Miryala, Muralidhar

AU - Murakami, Masato

PY - 2019/1/1

Y1 - 2019/1/1

N2 - Silver addition has been known to improve mechanical and superconducting performance of bulk magnesium boride (MgB2) superconductor synthesized via solid state sintering. While formation of pinning phases and impurities such as Ag–Mg phases and MgO, respectively, responsible for high performance, part of the Mg in initial mixture will be expected to be consumed by silver. In this work, the authors add varied amounts of Mg systematically such as x: 2 (while x = 1.05, 1.075, 1.1, 1.125, 1.15) ratio of Mg:B instead of usual stoichiometric ratio of 1:2. To obtain high superconducting properties, the authors use carbon encapsulated boron (1.5% carbon) along with 4 wt% Ag. X-ray diffraction analysis shows the presence of Ag–Mg phases and minute amount of MgO. Superconducting quantum interference device (SQUID) measurements indicate that high irreversibility field (4.76 T) and large Jc of 520, 440, and 347 kA cm−2 at 10, 15, and 20 K, respectively, at self-field was exhibited in sample with x = 1.075. Flux pinning force studies are done to analyze the effect of secondary phases formed. All results analyzed explain the improved critical current performance based on nanometer-sized Ag–Mg particles in the final product.

AB - Silver addition has been known to improve mechanical and superconducting performance of bulk magnesium boride (MgB2) superconductor synthesized via solid state sintering. While formation of pinning phases and impurities such as Ag–Mg phases and MgO, respectively, responsible for high performance, part of the Mg in initial mixture will be expected to be consumed by silver. In this work, the authors add varied amounts of Mg systematically such as x: 2 (while x = 1.05, 1.075, 1.1, 1.125, 1.15) ratio of Mg:B instead of usual stoichiometric ratio of 1:2. To obtain high superconducting properties, the authors use carbon encapsulated boron (1.5% carbon) along with 4 wt% Ag. X-ray diffraction analysis shows the presence of Ag–Mg phases and minute amount of MgO. Superconducting quantum interference device (SQUID) measurements indicate that high irreversibility field (4.76 T) and large Jc of 520, 440, and 347 kA cm−2 at 10, 15, and 20 K, respectively, at self-field was exhibited in sample with x = 1.075. Flux pinning force studies are done to analyze the effect of secondary phases formed. All results analyzed explain the improved critical current performance based on nanometer-sized Ag–Mg particles in the final product.

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