Paramagnetic magnetization signals and curious metastable behaviour in field-cooled magnetization of a single crystal of superconductor 2H-NbSe2

TL;DR

This study investigates the paramagnetic Meissner effect in a single crystal of 2H-NbSe2, revealing metastable magnetization responses and behaviors similar to giant vortex states in mesoscopic superconductors.

Contribution

It provides new insights into the metastable and switching behaviors of field-cooled magnetization in 2H-NbSe2, linking experimental observations to theoretical vortex state predictions.

Findings

Paramagnetic magnetization exhibits metastability and random switching.

Magnetization behavior resembles giant vortex states in mesoscopic superconductors.

External perturbations induce transitions between different magnetization states.

Abstract

We present here some newer characteristics pertaining to paramagnetic Meissner effect like response in a single crystal of the low Tc superconducting compound 2H-NbSe2 via a detailed study of effects of perturbation on the field-cooled magnetization response. In the temperature range, where an anomalous paramagnetic magnetization occurs, the field-cooled magnetization response is found to be highly metastable: it displays a curious tendency to switch randomly from a given paramagnetic value to a diamagnetic or to a different paramagnetic value, when the system is perturbed by an impulse of an externally applied ac field. The new facets revealed in a single crystal of 2H-NbSe2 surprisingly bear a marked resemblance with the characteristics of magnetization behaviour anticipated for the giant vortex states with multiple flux quanta predicted to occur in mesoscopic-sized superconducting specimen and possible transitions amongst such states.