Probing the Ground State Properties of Iron-based Superconducting Pnictides and Related Systems by Muon-Spin Spectroscopy

TL;DR

This review discusses how muon-spin spectroscopy (SR) has been used to study magnetic properties, structural transitions, and superconducting states in iron-based superconductors, revealing insights into their unconventional superconductivity.

Contribution

It provides a comprehensive overview of SR applications in probing magnetic and superconducting properties of iron-based superconductors, highlighting its role in understanding their ground states.

Findings

SR characterizes magnetic states in layered iron-based systems.

It reveals the interplay between magnetism, structure, and superconductivity.

The technique measures magnetic penetration depth, informing on unconventional superconductivity.

Abstract

In this short review, we attempt to give a comprehensive discussion of studies performed to date by muon-spin spectroscopy (more precisely the relaxation and rotation technique, also know as \muSR technique) on the recently discovered layered iron-based superconductors. On one side, \muSR has been used to characterized the magnetic state of different families of layered iron-based systems. Similarly the subtle interplay of the magnetic state and the structural transition present in some families has been investigated. We will also discuss the information provided by this technique on the interaction between the magnetic state and the superconducting phase. Finally the \muSR technique has been used to investigate the magnetic penetration depth of the superconducting ground state. The study of its absolute value, temperature and magnetic field dependence provides crucial tests for investigating possible unconventional superconducting states in such systems.