Matrix-dependent cooperativity in spin crossover Fe(pyrazine)Pt(CN)4 nanoparticles

Abstract

Anisotropic nanoparticles of the Fe(pyrazine)Pt(CN)(4) network were prepared embedded in various matrices that revealed to have a dramatic effect on the cooperative spin crossover phenomena. By a judicious choice of the nature of the matrix and the control of interparticle distances, a hysteresis of 15 K was achieved close to room temperature for such nano-objects.

The disentangling of hysteretic spin transition, polymorphism and metastability in bistable thin films formed by sublimation of bis(scorpionate) Fe(ii) molecules

“…10 The lattice dynamic is currently considered in relation with the partial restoration of the hysteresis observed in the case of ultra--small nanoparticles. 11 The fact that well--defined but aggregated particles without any coating present a hysteresis identical 8 and even larger 12 than the bulk, was assigned to the interparticle coupling and to better crystallinity respectively. The friction between surfaces may account for the spreading of the hysteresis of a single nanocrystal in contact with a substrate.…”

“…The general trends observed by increasing their surface/volume ratio 5,6,7 are the loss of hysteresis due to the decrease of cooperativity, the downshift of the transition temperature and the incompleteness of the spin--state switching. Among other things, these effects derive from the nanoparticle surface (energies, strains) 8,9,10 and thus from their interfaces with the external environment. It has been established that the stabilization of HS (LS) residue with a down--(up--)shift of transition temperature (T 1/2 ) may be accounted for by the negative (positive) value of the difference between the HS and LS surface energy.…”

Preserving the spin transition properties of iron-triazole coordination polymers within silica-based nanocomposites

“…40 Other works reported the engineering of silica thin films with controlled porosity, doped with spin crossover particles. 21,[41][42][43][44] However, in the above-described strategies, the spin transition properties are usually modified compared to the solid-state systems.…”

Analysis of first order reversal curves in the thermal hysteresis of spin-crossover nanoparticles within the mechanoelastic model

“…This behavior has been interpreted in terms of a reduced cooperativity, as the use of open boundary conditions limits the effect of the long-range interactions. 5 In addition, comparing to bulk systems, the thermal transition in nanoparticle systems can be strongly affected by kinetic 6 or matrix 2,7 effects.…”

“…The study of spin-crossover nanoparticle systems has become a hot topic in the spin-crossover community over the last few years. [1][2][3] Several groups have synthesized spincrossover nanoparticles and have investigated their properties for possible applications as sensors or for data storage. 4 Consequently, several unexpected differences between nanoparticles and bulk compounds have been detected.…”