The effect of nano-alumina on structural and magnetic properties of MgB2 superconductors

Intikhab A. Ansari*, M. Shahabuddin, Khalil A. Ziq, A. F. Salem, V. P.S. Awana, M. Husain, H. Kishan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Nano-Al2O3 doped Mg1-xAlxB 2 with 0≤x≤6% were synthesized by solid state reaction at 750 °C in Fe tube encapsulation under a vacuum of 10-5Torr. Resistance measurement shows that the Tc decreases with x and zero resistivity for x ≤ 0 and 6% are obtained at 38 and 35K, respectively. XRD measurement shows that the lattice parameter and cell volume also decrease monotonically with increasing doping levels. From this we infer that the Al has been substituted in the lattice of MgB2 at Mg sites. Resistivity measurement shows a systematic decrease in Tc with doping which also confirms the substitution of Al. Magnetization studies in the temperature range from 4 to 35K and in the magnetic field up to 9T shows a significant increase in the irreversibility field (Hirr), critical current density (J c) and remanent magnetization (MR) with increasing concentration of the Al2O3 nanoparticle. At low fields we have observed large vortex instabilities (known as a vortex avalanche) associated with all doped samples. The vortex-avalanche effect is reduced with increasing temperature and vanishes near 20K. The results are discussed in terms of local-vortex instabilities caused by doping of Al2O3 nanoparticles.

Original languageEnglish
Article number018
Pages (from-to)827-831
Number of pages5
JournalSuperconductor Science and Technology
Volume20
Issue number8
DOIs
StatePublished - 1 Aug 2007

ASJC Scopus subject areas

  • Ceramics and Composites
  • Condensed Matter Physics
  • Metals and Alloys
  • Electrical and Electronic Engineering
  • Materials Chemistry

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