First Order Premelting Transition of Vortex Lattices

TL;DR

This paper proposes a two-step phase transition model for vortex lattices in high-temperature superconductors, emphasizing a premelting transition driven by vortex vacancies and interstitials, supported by experimental data.

Contribution

It introduces the concept of a premelting transition in vortex lattices, challenging the traditional single melting transition view.

Findings

Good agreement with experimental transition temperatures for YBCO and BSCCO.

Identification of vacancy and interstitial vortices as drivers of premelting.

Evidence supporting a two-step phase transition process.

Abstract

Vortex lattices in the high temperature superconductors undergo a first order phase transition which has thus far been regarded as melting from a solid to a liquid. We point out an alternative possibility of a two step process in which there is a first order transition from an ordinary vortex lattice to a soft vortex solid followed by another first order melting transition from the soft vortex solid to a vortex liquid. We focus on the first step. This premelting transition is induced by vacancy and interstitial vortex lines. We obtain good agreement with the experimental transition temperature versus field, latent heat, and magnetization jumps for YBCO and BSCCO.