# Slow Vortex Creep Induced by Strong Grain Boundary Pinning in Advanced Ba122 Superconducting Tapes

## TL;DR

This study investigates the vortex creep behavior in advanced Ba122 superconducting tapes, revealing temperature and magnetic field-dependent regimes influenced by strong grain boundary pinning, with implications for broad cryogenic applications.

## Contribution

It demonstrates the complex vortex creep regimes in Ba122 tapes and highlights the role of grain boundary pinning in their magnetic properties.

## Key findings

- Vortex creep exhibits a temperature-insensitive plateau below 10 K.
- Relaxation rate saturates with field below 20 K.
- Strong grain boundary pinning enhances potential applications.

## Abstract

We report the temperature, magnetic field and time dependences of magnetization in advanced Ba122 superconducting tapes. The sample exhibits a peculiar vortex creep behavior. Below 10 K, the normalized magnetization relaxation rate S=dln(-M)/dln(t) shows a temperature insensitive plateau with a value comparable to that of the low temperature superconductors, which can be explained within the framework of the collective creep theory. It then enters into a second collective creep regime when the temperature increases. Interestingly, the relaxation rate below 20 K tends to saturate with the increasing field. However, it changes to a power law dependence on field at a higher temperature. A vortex phase diagram composed of the collective and the plastic creep regions is concluded. Benefit from the strong grain boundary pinning, the advanced Ba122 superconducting tape has promising potential to be applied not only in liquid helium but also in liquid hydrogen or at the temperature accessible with cryocoolers.