Fizika Nizkikh Temperatur: Volume 27, Number 9-10 (September 2001), p. 991-1011    ( to contents , go back )

Vortex matter in superconductors

V. M. Pan

1Institute of Physics of Metalls of National Academy of Sciences of Ukraine, Vernadskogo ave. 36, Kiev 03142, Ukraine
E-mail: pan@imp.kiev.ua

A. V. Pan1

Institute for Superconducting and Electronic Materials, University of Wollongong, N. S. W. 2522, Australia
pos Анотація:

Received May 18, 2001

Abstract

The behavior of a vortex ensemble in high-temperature superconducting biaxially-oriented films YBa2 Cu3 O7-d (YBCO) at different orientations of applied magnetic field within Shubnikov`s phase has been studied. The study has been carried out by measuring the current-voltage characteristics, as well as the resonance frequency and damping curves with the transport current flowing through an oscillating superconductor. In contrast to single crystals, the behavior of vortices in the YBCO films is determined by their interactions with linear defects ≈ edge dislocations formed during film deposition due to the pseudomorphis epitaxial growth process. These dislocations are the dominating sort of crystal defects whose density can exceed 1015 lines/m2. Effective vortex pinning and high critical current density (Jc³3·1010 A/m2 at 77 K) in well-prepared perfect YBCO films are indeed caused by the high density of such linear defects. New phases of the vortex matter in YBCO films for quasi-statics and dynamics are found and studied. The interactions of vortices with crystal defects, different kinds of vortex lattice disorder, and complex depinning are shown to be responsible for these states. An H-T phase diagram for the vortex matter in the YBCO films is proposed.

PACS:
74.25.Dw - Superconductivity phase diagrams
74.60.-w -
74.72.Bk - Y-based cuprates
74.76.Bz -
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