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

Abstract

Magnetic hysteresis loops below 300 mK on single crystals of the Mn(II) -nitronyl nitroxide free radical chain (Mn(hfac)2(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 orders in this compound.

Magnetic order in the frustrated Ising-like chain compoundSr3NiIrO6

“…The spin dynamics could be attributed to the nucleation of domain walls along the chains. The energy barrier determined from the AC susceptibility measurement is thus the energy needed in order to create a domain wall involving an anisotropy barrier and intrachain interactions 22 . Our neutron diffraction study combined with symmetry analysis explaining the origin of the weak ferromagnetic component clearly favours the amplitude modulated model at low temperature.…”

1D CoII and NiII Chiral Polymers That Exhibit Ferromagnetic Interactions

“…Such noncentrosymmetric repartition of the spin carriers can greatly affect the bulk magnetic properties of the material as has been shown in some 1D coordination systems of metal with chiral nitroxide radical. [18][19][20][21] This might even give rise to new phenomena such as magnetochiral dichroism (MCD) and chiral wave propagation. In that context, high MCD has been recently observed in chiral Cr III compounds.…”

Crackling noise and avalanches in minerals

“…During 100 years of research many experimental methods were developed to quantify avalanches. They range from magnetic measurements to electrical depolarization currents in ferroelectrics and optical observations of crack patterns and the determination of fractal dimensions (Lung and Zhang 1989;Xie and Sanderson 1995;Lhotel et al 2008;McHugh et al 2009). Some experiments are conducted under in vivo conditions where the actual changes of domain structures are determined; others are post-mortem analyses where, e.g.…”