Magnetic measurements in NdBa2Cu3O7-δ single crystals: Magnetization, flux pinning and creep

Michael Rudolf Koblischka, T. Higuchi, S. I. Yoo, Masato Murakami, T. Frello, M. Baziljevich, T. H. Johansen, T. Wolf, P. Diko

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

In this paper, we present the results of various magnetic measurements on an NdBa2Cu3O7-δ (NdBCO) single crystal. Special features observed in the magnetization loops (MHLs) are discussed. From these loops, critical current densities, jc as a function of the applied field, Ha, and volume pinning forces, Fp =jc × B, are derived. The samples exhibit a strong fishtail or peak effect at temperatures above 30 K. In a small temperature window between 50 K and 74 K, even three peaks are seen in the jc(T,Ha) curves. A good scaling of the jc (T,Ha) curves is obtained, which allows the identification of the peaks. The scaled volume pinning forces (vs the reduced field, h = Ha/Hiir), in the temperature regime between 60 and 90 K give experimental evidence for a strong pinning at extended superconducting defects (interaction volume Vpin ∼ξ2d). These defects are ascribed to spatial composition fluctuations found in light rare earth superconductors, providing a scatter of the transition temperature, Tc. Furthermore, the scaling analysis of Fp is extended towards low temperatures. It is shown that at 5 K another peak in Fp is found, which is due to pinning at twin boundaries. Using this scaling analysis of both jc and Fp, the irreversibility line (IL) is determined in the entire temperature range 0-92 K. Magneto-optic (MO) imaging is employed to investigate the flux distributions of various NdBCO single crystals. These images confirm the important role of twin boundaries as pinning sites at low temperatures and low applied fields.

Original languageEnglish
Pages (from-to)225-234
Number of pages10
JournalApplied Superconductivity
Volume6
Issue number2-5
Publication statusPublished - 1998 Feb
Externally publishedYes

Fingerprint

Flux pinning
flux pinning
Magnetic variables measurement
magnetic measurement
Magnetization
Creep
Single crystals
magnetization
single crystals
scaling
Temperature
temperature
defects
magneto-optics
curves
Magnetooptical effects
Defects
critical current
rare earth elements
Rare earths

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Magnetic measurements in NdBa2Cu3O7-δ single crystals : Magnetization, flux pinning and creep. / Koblischka, Michael Rudolf; Higuchi, T.; Yoo, S. I.; Murakami, Masato; Frello, T.; Baziljevich, M.; Johansen, T. H.; Wolf, T.; Diko, P.

In: Applied Superconductivity, Vol. 6, No. 2-5, 02.1998, p. 225-234.

Research output: Contribution to journalArticle

Koblischka, MR, Higuchi, T, Yoo, SI, Murakami, M, Frello, T, Baziljevich, M, Johansen, TH, Wolf, T & Diko, P 1998, 'Magnetic measurements in NdBa2Cu3O7-δ single crystals: Magnetization, flux pinning and creep', Applied Superconductivity, vol. 6, no. 2-5, pp. 225-234.
Koblischka, Michael Rudolf ; Higuchi, T. ; Yoo, S. I. ; Murakami, Masato ; Frello, T. ; Baziljevich, M. ; Johansen, T. H. ; Wolf, T. ; Diko, P. / Magnetic measurements in NdBa2Cu3O7-δ single crystals : Magnetization, flux pinning and creep. In: Applied Superconductivity. 1998 ; Vol. 6, No. 2-5. pp. 225-234.
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