Magnetic properties of two-phase superconductors

TL;DR

This paper introduces a theoretical model for two-phase superconductors with distinct order parameters, revealing unique magnetic behaviors such as temperature-dependent penetration length and variable superconductor type.

Contribution

It presents a novel theoretical framework for two-phase superconductors, highlighting observable magnetic differences from traditional models and analyzing their temperature-dependent properties.

Findings

London penetration length is strongly reduced at low temperatures.

Ginzburg-Landau parameter varies with temperature.

Superconductor type depends on the ratio of critical temperatures.

Abstract

We have recently proposed a theoretical model for superconductors endowed with two distinct superconducting phases, described by two scalar order parameters which condensate at different critical temperatures. On analyzing the magnetic behavior of such systems, we have found some observable differences with respect to the case of ordinary Ginzburg-Landau superconductors. In particular, at low temperature the London penetration length is strongly reduced and the Ginzburg-Landau parameter k becomes a function of temperature. By contrast, in the temperature region between the two phase transitions k is constant and the system is a type-I or a type-II superconductor depending on the ratio between the critical temperatures.