Magnetic Avalanches in Molecular Magnets

TL;DR

This paper reviews experimental findings on magnetic avalanches in molecular nanomagnets, focusing on how collective spin reversals occur via deflagration fronts, contrasting with quantum tunneling processes.

Contribution

It provides a comprehensive overview of experimental observations related to magnetic deflagration in molecular magnets, highlighting the phenomena's characteristics and underlying mechanisms.

Findings

Magnetic avalanches involve a deflagration front traveling through the sample.

Magnetic avalanches occur at subsonic speeds.

Experimental results support the collective spin reversal mechanism.

Abstract

The reversal of the magnetization of crystals of molecular magnets that have a large spin and high anisotropy barrier generally proceeds below the blocking temperature by quantum tunneling. This is manifested as a series of controlled steps in the hysteresis loops at resonant values of the magnetic field where energy levels on opposite sides of the barrier cross. An abrupt reversal of the magnetic moment of the entire crystal can occur instead by a process commonly referred to as a magnetic avalanche, where the molecular spins reverse along a deflagration front that travels through the sample at subsonic speed. In this chapter, we review experimental results obtained to date for magnetic deflagration in molecular nanomagnets.