Irreversibility line and low-field grain-boundary pinning in electron-doped superconducting thin films

TL;DR

This study investigates the irreversibility line and grain-boundary pinning in electron-doped superconducting thin films, revealing how film homogeneity affects magnetic properties and pinning strength.

Contribution

It introduces a detailed analysis of the irreversibility line and grain-boundary pinning in PCCO and SCCO thin films, highlighting the impact of film homogeneity on magnetic behavior.

Findings

Irreversibility line varies with film homogeneity.

Granular SCCO films exhibit four times higher pinning-force densities.

Critical-state model effectively describes the magnetic response.

Abstract

AC magnetic susceptibilities of electron-doped Pr_{1.85}Ce_{0.15}CuO_4 (PCCO) and Sm_{1.85}Ce_{0.15}CuO_4 (SCCO) granular thin films have been measured as a function of temperature and magnetic-field strength. Depending on the level of homogeneity of our films, two different types of the irreversibility line (IL) defined as the intergrain-loss peak temperature in the imaginary part of susceptibility have been found. The obtained results are described via the critical-state model taking into account the low-field grain-boundary pinning. The extracted pinning-force densities in more granular SCCO films turn out to be four times larger than their counterparts in less granular PCCO films.