In Situ AFM Imaging of Microstructural Changes Associated with The Spin Transition in [Fe(Htrz)2(Trz)](Bf4) Nanoparticles

Abstract

Topographic images of [Fe(Htrz) 2 (trz)](BF 4 ) nanoparticles were acquired across the first-order spin transition using variable-temperature atomic force microscopy (AFM) in amplitude modulation mode. These studies revealed a complex morphology of the particles consisting of aggregates of small nanocrystals, which expand, separate and re-aggregate due to the mechanical stress during the spin-state switching events. Both reversible (prompt or slow recovery) and irreversible effects (fatigue) on the particle morphology were evidenced and correlated with the spin crossover properties.

Mosaicity of Spin-Crossover Crystals

“…These observations deserve further investigation. It is nevertheless clear that SCO degrades the sample through a form of mechanical fatigability, as already observed in other SCO materials [16,17]. It can be noted that there are no significant effects of this mechanical degradation on the magnetic characterization of the SCO, since the magnetic curve is not affected by repeated cycles [13].…”

Coupling Mechanical and Electrical Properties in Spin Crossover Polymer Composites

“…This irreversibility of the first heating transition is wellknown for many SCO materials ("run-in" phenomenon) and can be attributed to various phenomena such as the loss of solvents and/or particle morphology changes, and/or polymorphism. [30,31] For this reason, we show material properties observed during the second (stable) thermal cycle, except otherwise stated.…”

Crystallinity and Microstructural Versatility in the Spin‐Crossover Polymeric Material [Fe(Htrz)2(trz)](BF4)

“…[15] One of the rare reported investigations, however, concerned the present compound and showed, first, that it is possible to extract reliable sizes and morphologies of coherent domains in these materials and, secondly, that SCO can engender a mechanical fatigability. [15,16] The present study aims to provide new information on the microstructural properties of the title SCO material in the form of a crystalline powder.…”