Exploring metastability via the third harmonic measurements in single crystals of $2H$-$NbSe_2$ showing anomalous Peak effect

TL;DR

This study investigates metastability effects in $2H$-$NbSe_2$ crystals through third harmonic ac susceptibility measurements, revealing insights into the peak effect and the limiting temperature for critical current density.

Contribution

It introduces third harmonic ac susceptibility as a tool to identify the spinodal temperature and metastability effects in the peak effect phenomenon.

Findings

Third harmonic data indicates the spinodal temperature.

Metastability effects are linked to the peak effect in $J_c$.

Third harmonic measurements effectively locate the limiting temperature.

Abstract

We explore the metastability effects across the order-disorder transition pertaining to the peak effect phenomenonon in critical current density ($J_c$) via the first and the third harmonic ac susceptibility measurements in the weakly pinned single crystals of $2H$-$NbSe_2$. An analysis of our data suggests that an imprint of the limiting (spinodal) temperature above which $J_c$ is path independent can be conveniently located in the third harmonic data ($\chi_{3\omega}^{\prime}$).