Reentrant Peak Effect in an anisotropic superconductor 2H-NbSe_2 : Role of disorder

TL;DR

This study investigates the reentrant Peak Effect in 2H-NbSe_2, revealing how disorder influences the vortex phase transitions and demonstrating the effect's robustness and sensitivity in different disorder regimes.

Contribution

It provides experimental evidence of the reentrant Peak Effect in 2H-NbSe_2 and analyzes how varying disorder levels affect the vortex phase diagram.

Findings

Reentrant Peak Effect observed in 2H-NbSe_2 single crystals.

Disorder reduces the (H,T) stability region of vortex order.

The upper PE branch is robust, while the reentrant branch is highly sensitive to disorder.

Abstract

The reentrant nature of Peak Effect is established in a single crystal of 2H-NbSe_2 via electrical transport and dc magnetisation studies. The role of disorder on the reentrant branch of PE has been examined in three single crystals with varying levels of quenched random disorder. Increasing disorder presumably shrinks the (H,T) parameter space over which vortex array retains spatial order. Although, the upper branch of the PE curve is somewhat robust, the lower reentrant branch of the same curve is strongly affected by disorder.