Quantum deflagration and supersonic fronts of tunneling in molecular magnets

TL;DR

This paper models magnetic deflagration in molecular magnets, revealing that spin tunneling can cause supersonic front speeds and complex spatial profiles, advancing understanding of quantum effects in magnetic phenomena.

Contribution

It introduces a realistic model incorporating dipolar-controlled spin tunneling, showing how tunneling resonances influence front speed and structure in molecular magnets.

Findings

Front speed peaks at tunneling resonances.

High transverse fields can induce supersonic front speeds.

Spatial profiles show tunneling-triggered burning fronts.

Abstract

Theory of magnetic deflagration taking into account dipolar-controlled spin tunneling has been applied to the realistic model of molecular magnet Mn_12 Ac. At small transverse field, the front speed v has tunneling maxima on the bias field B_z reflecting those of the molecular spin's relaxation rate calculated from the density-matrix equation. At high transverse field, spin tunneling directly out of the metastable ground state leads to front speeds that can exceed the speed of sound. Both for the weak and strong transverse field, the spatial profile of the deflagration front near tunneling resonances shows a front of tunneling that triggers a burning front behind it.