Spin-polarized muons in condensed matter physics

TL;DR

This paper discusses how spin-polarized muons are used as probes in condensed matter physics to investigate magnetic, superconducting, and molecular properties through their spin precession and relaxation behaviors.

Contribution

It reviews experimental techniques involving implanted muons and highlights recent applications across various condensed matter phenomena.

Findings

Muons reveal insights into magnetism and superconductivity.

Applications include studies of semiconductors and spin systems.

Muon techniques have advanced understanding of quantum diffusion.

Abstract

A positive muon is a spin-1/2 particle. Beams of muons with all their spins polarized can be prepared and subsequently implanted in various types of condensed matter. The subsequent precession and relaxation of their spins can then be used to investigate a variety of static and dynamic effects in a sample and hence to deduce properties concerning magnetism, superconductivity and molecular dynamics. Though strictly a lepton, and behaving essentially like a heavy electron, it is convenient to think of a muon as a light proton, and it is often found with a captured electron in a hydrogen-like atom known as muonium. This article outlines the principles of various experimental techniques which involve implanted muons and describes some recent applications. The use of muons in condensed matter physics has shed new light on subjects as diverse as passivation in semiconductors, frustrated spin systems, vortex lattice melting, and quantum diffusion of light particles.