Eur. Phys. J. B 50, 565-569 (2006)
https://doi.org/10.1140/epjb/e2006-00180-3

Flux trapping in a macroscopic cylinderical hole drilled in Bi-Sr-Ca-Cu-O

¹ Abant Izzet Baysal University, Department of Physics, Turgut Gulez Research Laboratory, 14280 Bolu, Turkey
² National Metrology Institute TUBITAK P.O. Box 21, 41470, Gebze-Kocaeli, Turkey

Corresponding author: ^a kilic_a@ibu.edu.tr

Received: 7 December 2005
Revised: 4 March 2006
Published online: 17 May 2006

Abstract

The flux dynamics in a polycrystalline sample of Bi_1.7Pb_0.3Sr₂Ca₂Cu₃O_x with a macroscopic cylindrical hole (CH) drilled was investigated by slow transport relaxation (V-t curves) and magnetovoltage measurements (V-H curves). It was monitored that there are several discontinuities in the time evolution of quenched state in V-t curves, which was attributed to the leaving of quantized flux lines trapped through CH together with surface superconducting effects. We observed that asymmetric V-H curves demonstrate unusual remarkable counter clockwise hysteresis effects upon cycling of field. This interesting result was correlated mainly to the flux trapping inside the CH that acts as a macroscopic attractive pinning center for flux lines. Further, the hysteresis effects in V-H curves for a fixed transport current provide a direct evidence that the number of flux lines, measured dissipation and relative decrease/increase in irreversibilities could be determined by sweeping rate of external magnetic field (dH/dt) which leads also to peculiar time effects.