Vortex phase diagram in BSCCO with damage tracks created by 30 MeV fullerene irradiation

TL;DR

This study demonstrates that 30 MeV fullerene irradiation creates dense, nanometer-scale tracks in BSCCO superconductors, significantly enhancing vortex pinning and altering the vortex phase diagram.

Contribution

It introduces a novel irradiation method using fullerene ions to produce effective vortex pinning centers in BSCCO, revealing new features in the vortex phase diagram.

Findings

Enhanced critical current density and magnetic irreversibility line.

Presence of first order vortex phase transition in irradiated crystals.

Exponential Bose-glass line independent of pinning potential.

Abstract

Using 30 MeV C60 fullerene irradiation, we have produced latent tracks of diameter 20 nm and length 200 nm, near the surface of single crystalline BSCCO. A preliminary transmission electron microscopy study shows evidence for a very high density of deposited energy, and the ejection of material from the track core in very thin specimens. The latent tracks reveal themselves to be exceptionally strong pinning centers for vortices in the superconducting mixed state. Both the critical current density and magnetic irreversibility line are significantly enhanced. The irradiated crystals present salient features of the (B,T) phase diagram of vortex matter both of pristine crystals, such as the first order vortex phase transition, and the exponential Bose-glass line characteristic of heavy ion-irradiated crystals. We show that the latter is manifestly independent of the pinning potential.