Effective Vortex Pinning in MgB2 thin films

TL;DR

This paper investigates vortex pinning mechanisms in MgB2 thin films grown by PLD and EB evaporation, identifying key factors that enhance pinning and their effects on superconducting properties.

Contribution

It reveals how different fabrication methods influence defect structures and vortex pinning, providing insights for optimizing MgB2 thin film performance.

Findings

EB process creates small grain boundary defects enhancing pinning without reducing Tc.

PLD induces structural disorder that improves pinning but lowers Tc.

Different growth techniques lead to distinct vortex pinning mechanisms.

Abstract

We discuss pinning properties of MgB2 thin films grown by pulsed-laser deposition (PLD) and by electron-beam (EB) evaporation. Two mechanisms are identified that contribute most effectively to the pinning of vortices in randomly oriented films. The EB process produces low defected crystallites with small grain size providing enhanced pinning at grain boundaries without degradation of Tc. The PLD process produces films with structural disorder on a scale less that the coherence length that further improves pinning, but also depresses Tc.