New aspects in the Bragg Glass-Disordered phase transition: an analysis based on the 3rd harmonics of the AC magnetic susceptibility

TL;DR

This paper introduces a novel method using the 3rd harmonics of AC magnetic susceptibility to detect the Bragg Glass to Disordered phase transition in vortex lattices of type-II superconductors, even when the Peak Effect is absent.

Contribution

It presents a new experimental approach to identify the phase transition without relying on the Peak Effect, confirmed through studies on V3Si single crystals.

Findings

The method detects phase transition in conditions where Peak Effect is not observed.

Experimental confirmation on V3Si crystals extends the understanding of vortex phase transitions.

The approach aligns with theoretical predictions for high field/low temperature regimes.

Abstract

We analyse the phase transition between the Bragg Glass and the Disordered phase in the vortex lattice in type-II superconductors, both by analytical computations and experimental investigations. It is known that if the Peak Effect can be detected, a Bragg Glass/Disordered phase transition takes place. We show that, in some conditions, this transition can occur without the observation of the Peak Effect Phenomenon. We introduce a method based on the 3rd harmonics of the AC magnetic susceptibility to detect the transition also in these cases. Using this method, we obtain an experimental confirmation of the theoretical predictions on sphere shaped V3Si single crystals, in the high fields/low temperatures range too, where previous experimental studies failed to detect the Bragg/Disordered phase transition.