A new method to detect the vortex glass phase and its evidence in YBCO

TL;DR

This paper introduces a novel AC magnetic susceptibility method to detect the vortex glass phase in type II superconductors, demonstrating its effectiveness over traditional transport measurements and confirming its application in YBCO samples.

Contribution

The paper presents a new frequency-dependent analysis technique of AC magnetic susceptibility to identify the vortex glass phase, validated through numerical simulations and experimental application in YBCO.

Findings

The method effectively distinguishes the vortex glass phase from other disordered phases.

Numerical simulations reveal specific magnetic fingerprints of the vortex glass phase.

Successful experimental detection of the vortex glass phase in YBCO samples.

Abstract

The Vortex Glass phase has been unequivocally identified by analyzing the non linear magnetic response of type II superconductors. The method here introduced, more effective than the study of direct transport measurements, is based on a combined frequency dependence analysis of the real and imaginary part of the 1st and 3rd harmonics of the AC magnetic susceptibility. The analysis has been performed by taking into account both the components and the Cole-Cole plots (i.e. the imaginary part as a function of the real part). Numerical simulations have been used to individuate the fingerprints of the magnetic behaviour in the Vortex Glass phase. These characteristics allowed to distinguish the Vortex Glass phase from the other disordered phases, even those showing similar electrical properties. Finally, this method has been successfully applied to detect the Vortex Glass Phase in an YBCO bulk melt-textured sample.