Dissipative flux motion in YBa2Cu3−xFexO7−δ single crystals

✍ Scribed by M.D. Lan; J.Z. Liu; Y.X. Jia; Lu Zhang; Y. Nagata; P. Klavins; R.N. Shelton

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 489 KB
• Volume: 218
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/0921-4534(93)90267-t

✦ Synopsis

The dissipative flux motion under magnetic fields has been studied in YBa2Cu,_$e,0,_b (x=0,0.04, and 0.13) single crystals. The thermally activated flux-creep model was used to analyze the resistivity data within the transition region. Temperature and field dependence of the activation energy can be scaled as U( F, H) _ ( 1

-T/T,(H))'/H.

In general, the activation energy is larger for H 11 ab-plane than for Hlabplane. This effect can account for the relative broadening of the resistive transition in the two field orientations. The optimum tits to U( F, H) provide values of the anisotropic superconducting parameters H&(O) and < for our crystals with varying Fe concentration. The crossover temperature that delineates the phase boundary between thermally activated flux-creep processes and flux flow will also be discussed.