New features of the phase transition to superconducting state in thin films

TL;DR

This paper investigates the fluctuation-induced phase transition changes in thin superconducting films, revealing that the Halperin-Lubensky-Ma effect is most pronounced in materials with high critical magnetic fields, contrary to previous beliefs.

Contribution

It provides numerical analysis of the HLM effect in thin films, showing its prominence in high $H_{c0}$ materials and discussing experimental observation possibilities.

Findings

HLM effect occurs more strongly in high $H_{c0}$ superconducting films.

Numerical data on free energy, latent heat, and specific heat for W, Al, In.

Influence of film thickness and material parameters on phase transition properties.

Abstract

The Halperin-Lubensky-Ma (HLM) effect of a fluctuation-induced change of the order of phase transition in thin films of type I superconductors with relatively small Ginzburg-Landau number $\kappa$ is considered. Numerical data for the free energy, the order parameter jump, the latent heat, and the specific heat of W, Al and In are presented to reveal the influence of film thickness and material parameters on the properties of the phase transition. We demonstrate for the first time that in contrast to the usual notion the HLM effect occurs in the most distinct way in superconducting films with high critical magnetic field $H_{c0}$ rather than in materials with small $\kappa$. The possibility for an experimental observation of the fluctuation change of the order of superconducting phase transition in superconducting films is discussed.