Intrinsic avalanches and collective phenomena in a Mn(II)-free radical ferrimagnetic chain

TL;DR

This paper investigates intrinsic magnetization avalanches in a Mn(II)-free radical chain at very low temperatures, revealing their relation to domain-wall nucleation and magnetic order competition.

Contribution

It demonstrates that avalanche fields are intrinsic and independent of sample, linking avalanches to domain-wall nucleation and magnetic order dynamics.

Findings

Avalanches occur at a constant field below 200 mK.

Avalanches are triggered by domain-wall nucleation.

Competing magnetic orders influence avalanche mechanisms.

Abstract

Magnetic hysteresis loops below 300 mK on single crystals of the Mn(II) - nitronyl nitroxide free radical chain (Mn(hfac)_2({\it R})-3MLNN) present abrupt reversals of the magnetization, or avalanches. We show that, below 200 mK, the avalanches occur at a constant field, independent of the sample and so propose that this avalanche field is an intrinsic property. We compare this field to the energy barrier existing in the sample and conclude that the avalanches are provoked by multiple nucleation of domain-walls along the chains. The different avalanche field observed in the zero field cooled magnetization curves suggests that the avalanche mechanisms are related to the competition between ferromagnetic and antiferromagnetic order in this compound.