Counterpart of the Darrieus-Landau instability at a magnetic deflagration front

TL;DR

This paper investigates the magnetic instability at the spin avalanche front in molecular magnets, drawing parallels with classical combustion instabilities, and explores how quantum effects and crystal orientation influence this phenomenon.

Contribution

It introduces an analysis of magnetic deflagration front instability, including quantum tunneling effects and orientation dependence, extending classical combustion instability concepts to magnetic systems.

Findings

Quantum tunneling resonances increase growth rate

Instability can lead to transition from deflagration to detonation

Crystal orientation affects stability properties

Abstract

The magnetic instability at the front of the spin avalanche in a crystal of molecular magnets is considered. This phenomenon reveals similar features with the Darrieus-Landau instability, inherent to classical combustion flame fronts. The instability growth rate and the cut-off wavelength are investigated with respect to the strength of the external magnetic field, both analytically in the limit of an infinitely thin front and numerically for finite-width fronts. The presence of quantum tunneling resonances is shown to increase the growth rate significantly, which may lead to a possible transition from deflagration to detonation regimes. Different orientations of the crystal easy axis are shown to exhibit opposite stability properties. In addition, we suggest experimental conditions that could evidence the instability and its influence on the magnetic deflagration velocity.