Equilibrium magnetization in the vicinity of the first order phase transition in the mixed state of high-Tc superconductors

TL;DR

This study analyzes magnetization data near a first order phase transition in high-Tc superconductors, revealing that the magnetization difference across the transition varies in sign, challenging the vortex melting interpretation.

Contribution

It provides a scaling analysis of magnetization curves showing that the magnetization difference can be positive or negative, questioning the universal vortex melting scenario.

Findings

Magnetization difference sign varies across samples.

Results challenge the vortex melting interpretation.

Scaling analysis applied to literature data.

Abstract

We present the results of a scaling analysis of isothermal magnetization M(H) curves measured in the mixed state of high-Tc superconductors in the vicinity of the established first order phase transition. The most surprising result of our analysis is that the difference between the magnetization above and below the transition may have either sign, depending on the particular chosen sample. We argue that this observation, based on M(H) data available in the literature, is inconsistent with the interpretation that the well known first order phase transition in the mixed state of high-Tc superconductors always represents the melting transition in the vortex system.