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Enhanced superconducting properties of rare-earth oxides and graphene oxide added MgB₂

  • Sudesh Department of Physics, Indian Institute of Technology Roorkee, Uttarakhand, India
  • Das, Saikat Department of Physics and Fribourg Centre for Nanomaterials-FriMat, University of Fribourg, Switzerland
  • Bernhard, Christian Department of Physics and Fribourg Centre for Nanomaterials-FriMat, University of Fribourg, Switzerland
  • Varma, G.D. Department of Physics, Indian Institute of Technology Roorkee, Uttarakhand, India
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    15.10.2014
Published in:
  • Physica C: Superconductivity. - 2014, vol. 505, p. 32–38
superconductor
Critical temperature
Critical current density
Flux pinning
MgB₂
English In this paper, the effects of addition of (i) graphene oxide (GO), (ii) a series of rare-earth (RE, RE = La, Sm, Eu, Gd, Tb and Ho) oxides (REO) and (iii) a mixture of GO and rare-earth oxides (GO + REO) on the superconducting properties of MgB₂, have been studied with the help of electrical transport and magnetic measurements. All the samples have been prepared following the standard solid-state reaction route. We have used an optimum value of 1 wt% REO and 3 wt% GO for addition on the basis of previous studies. X-ray diffraction studies confirm the formation of hexagonal crystal structure (space group P6/mmm) of MgB₂ with small amounts of REBx (x = 4 and 6) and MgO impurity phases in all the synthesized samples. We observe that the critical current density, Jc and upper critical field Hc2(0) improve significantly in the REO-added and GO-added samples with no significant change in critical temperature, Tc. A substantial enhancement in Jc(H) and Hc2(0) is observed with the GO + REO addition in MgB₂. The different flux pinning mechanisms in all the samples are studied and it is found that the point pinning is the dominant mechanism in the GO-added samples and grain boundary pinning is the dominant one in the REO added samples. We have seen the combined effect of both types of flux pinning mechanisms in GO + REO added MgB₂.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
License undefined
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Persistent URL
https://folia.unifr.ch/unifr/documents/304032
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