Anisotropic flux creep in Bi2212:Pb single crystal in crossed magnetic fields

TL;DR

This study investigates how magnetic flux penetrates and relaxes in Bi2212:Pb single crystals under crossed magnetic fields, revealing anisotropic flux creep and laminar structure effects at low temperatures.

Contribution

It provides experimental evidence of anisotropic flux creep and flux line structure in Bi2212:Pb crystals using magneto-optic techniques.

Findings

Flux creep rate is anisotropic below 54 K.

Three-dimensional flux line structure confirmed at low temperatures.

Flux relaxation exhibits asymmetry related to laminar structure.

Abstract

An experimental study of magnetic flux penetration under crossed magnetic fields in Bi2212:Pb single crystals is performed by the magneto-optic technique. The anisotropy of the flux creep rate induced by the in-plane magnetic field is observed at $T<54\pm 2$ K. This observation confirms the existence of the three-dimensional flux line structure in Bi2212:Pb at low temperatures. An asymmetry of the flux relaxation with respect to the direction of the in-plane field is found. This effect can be attributed to the influence of the laminar structure on the pinning in Bi2212:Pb single crystals.