The displacement and annihilation of macroscopic regions with hypervortices in ceramic YBa2Cu3O7-x

TL;DR

This study experimentally investigates how macroscopic regions with frozen magnetic fields in ceramic YBa2Cu3O7-x can be displaced or annihilated using transport currents, revealing the roles of pinning forces and Lorenz forces in these processes.

Contribution

It provides new insights into the controllable manipulation of frozen magnetic fields in ceramic superconductors through transport currents.

Findings

Displacement occurs when FMF regions are below Hc1g due to weak pinning.

Transport current influences FMF mobility and magnitude.

Regions with FMF above Hc1g are not displaced due to stronger pinning.

Abstract

Features of the controllable displacement, annihilation, and transformation of macroscopic regions of a weak frozen magnetic field (FMF) have been experimentally studied in a plate of granulated ceramic YBa2Cu3O7-x under the action of the transport current flowing through it. It is shown that the displacement of regions with an FMF lower than the first critical field of the ceramic granules (Hc1g) is associated with a relatively weak pinning force of the hypervortices that is less than the maximum experimentally attainable Lorenz force. A discussion is presented of the role of the transport current that not only is one of the conditions for the appearance of the Lorenz force but also acts on the internal current structure of the local FMF, which in turn influences its mobility and magnitude. If a local field greater than Hc1g is frozen in, the experimentally produced Lorenz force is less than the pinning force of the Abrikosov vortices in the mixed state of the granules, and there is no displacement of the regions with an FMF.