Three Magnetization Peaks in HgBa$_2$Ca$_2$Cu$_3$O$_8$ Single Crystals

TL;DR

This study reports the discovery of three distinct magnetization peaks in HgBa$_2$Ca$_2$Cu$_3$O$_8$ single crystals, providing new insights into vortex dynamics and phase transitions in high-temperature superconductors.

Contribution

It introduces the observation of three magnetization peaks in a single superconductor, expanding the understanding of vortex behavior beyond previous two-peak observations.

Findings

Three magnetization peaks observed in HgBa$_2$Ca$_2$Cu$_3$O$_8$ crystals.

The second peak relates to an order-disorder transition.

The third peak is linked to elastic-plastic vortex crossover.

Abstract

By measuring magnetization hysteresis loops of the superconducting HgBa$_2$Ca$_2$Cu$_3$O$_8$ single crystals ($T_{\rm c}$ = 133 K), we observed three magnetization peaks in a wide temperature region. This is in contrast to the previous observation that there are only two magnetization peaks in many superconductors. Detailed analysis finds that the second peak here evolves from a kinky structure at low temperatures and gets enhanced at high temperatures; the third peak evolves from a general broad peak at low temperatures and evolves into a sharp peak and even a step-like one at high temperatures. We propose a general phase diagram to interpret these peaks, the second peak is corresponding to the order-disorder transition, while the third peak is associated with the elastic-plastic crossover. Our work unifies the understanding of different "second peak" structures in different systems and thus sheds new light in understanding the vortex dynamics in type-II superconductors.