Lattice Defects in Sub-Micrometer Spin-Crossover Crystals Studied by Electron Diffraction

Acoustic emissions from spin crossover complexes

“…24 Structural fatigability in a nanocrystalline sample of 2 has been also inferred from in situ atomic force microscopy and electron diffraction imaging experiments. 23,26 These measurements revealed significant, partially reversible changes of grain boundary morphologies as well an irreversible degradation of the particles manifested by the ''peeling'' of their surface layer. Besides first-order phase transformations, quite a large number of phenomena are known to produce crackling noises such as earthquakes, sand-piles, plastic deformation, Barkhausen noise, ferroelastic or porous materials.…”

“…24 Structural fatigability in a nanocrystalline sample of 2 has been also inferred from in situ atomic force microscopy and electron diffraction imaging experiments. 23,26 These measurements revealed significant, partially reversible changes of grain boundary morphologies as well an irreversible degradation of the particles manifested by the “peeling” of their surface layer.…”

“…In contrast, much less is known about the microstructural changes associated with the SCO, such as the variation of the size and shape of crystalline domains, the mosaicity in crystals, micro-constraints and grain boundaries in powder samples and, in general, about the formation of structural defects. [22][23][24][25][26] One of the most spectacular examples for microstructural changes was reported for the compound [Fe(DAPP)(abpt)](ClO 4 ) 2 (DAPP = bis(3-aminopropyl)(2-pyridylmethyl)amine, abpt = 4-amino-3,5bis(pyridin-2-yl)-1,2,4-triazole), whose crystals were literally pulverized by thermal cycling around the spin transition (ca. 20 cycles).…”