Dynamic contribution to the fishtail effect in a twin-free DyBa2Cu3O7-δ single crystal

A. J.J. van Dalen, Michael Rudolf Koblischka, R. Griessen, M. Jirsa, G. Ravi Kumar

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Superconducting current densities js and dynamic relaxation rates Q d ln js/d In(dBe/dt), where dBe/dt is the sweep rate of the external magnetic field Be, were measured as a function of temperature (5 K < T < 65 K) in magnetic fields up to 7 T on a twin-free DyBa2Cu3O7-δ single crystal by means of a high-sensitivity capacitance torque magnetometer. Above 15 K, we observe a "fishtail" effect, i.e. a pronounced minimum in the js(Be) curve at fields around Be = 1 T. The relaxation rate Q shows an anomalous increase at low fields which is correlated to the minimum in the js(Be) curve. Both the js versus Be and Q versus Be data are used as input parameters into the generalized inversion scheme developed by Schnack et al. [Phys. Rev. B 48 (1993) 13178] to calculate the true critical current density jc which is by definition independent of relaxation effects. Interestingly, the jc(Be, T) curves derived in this way do not show a minimum. This points clearly to a dynamic contribution to the fishtail effect. The true critical current density jc(Be, T) decreases weakly with increasing Be over the entire measured temperature and field range, as expected for single-vortex pinning. This indicates that the observed fishtail effect is not caused by a crossover from single-vortex pinning to pinning of flux bundles. The temperature dependence of jc is in good agreement with the predictions of a model based on single-vortex pinning caused by spatial fluctuations in the charge-carrier mean free path.

Original languageEnglish
Pages (from-to)265-274
Number of pages10
JournalPhysica C: Superconductivity and its Applications
Volume250
Issue number3-4
DOIs
Publication statusPublished - 1995 Aug 15
Externally publishedYes

Fingerprint

Vortex flow
Single crystals
single crystals
vortices
current density
Magnetic fields
critical current
curves
Magnetometers
Charge carriers
Temperature
Capacitance
Current density
Torque
magnetic fields
mean free path
magnetometers
Fluxes
bundles
torque

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering

Cite this

Dynamic contribution to the fishtail effect in a twin-free DyBa2Cu3O7-δ single crystal. / van Dalen, A. J.J.; Koblischka, Michael Rudolf; Griessen, R.; Jirsa, M.; Ravi Kumar, G.

In: Physica C: Superconductivity and its Applications, Vol. 250, No. 3-4, 15.08.1995, p. 265-274.

Research output: Contribution to journalArticle

van Dalen, A. J.J. ; Koblischka, Michael Rudolf ; Griessen, R. ; Jirsa, M. ; Ravi Kumar, G. / Dynamic contribution to the fishtail effect in a twin-free DyBa2Cu3O7-δ single crystal. In: Physica C: Superconductivity and its Applications. 1995 ; Vol. 250, No. 3-4. pp. 265-274.
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