MAGNETIC PROPERTIES OF UNCONVENTIONAL SUPERCONDUCTORS

TL;DR

This paper reviews recent advances in understanding the magnetic properties of unconventional superconductors, focusing on symmetry breaking, vortex structures, and phase transitions within the mixed state using phenomenological and theoretical approaches.

Contribution

It provides a comprehensive classification of vortex states and phase transitions in unconventional superconductors based on symmetry and phenomenological models.

Findings

Classification of vortex types near Hc1

Analysis of phase transitions at Hc2

Identification of vortex lattice structures

Abstract

The article reviews recent developments on magnetic properties of superconductors with anisotropic Cooper pairing. In particular, we show how the concept of broken symmetries is applied to the investigation of the mixed state in superconductors with a multicomponent order parameter. Starting from the phenomenological description in the framework of the generalized Ginzburg-Landau theory, we discuss different types of quantized vortices appearing at $H_{c1}$ in states with and without time-reversal breaking. General classification of superconducting phase transitions in a uniform magnetic field at $H_{c2}$ is constructed. Vortex lattices of different forms are found in the vicinity of the upper critical field. Symmetry arguments are used to classify phase transitions inside the mixed state. Special attention is given to results which can be obtained analytically. Also special emphasis is put on the open questions of the theory.