Hysteretic behavior of Fe(phen)2(NCS)2 spin-transition microparticles vs. the environment: A huge reversible component resolved by first order reversal curves

Tanasa, Radu; Laisney, Jérôme; Stancu, Alexandru; Boillot, Marie‐Laure; Enachescu, Cristian

doi:10.1063/1.4862748

Cited by 26 publications

(26 citation statements)

References 30 publications

(20 reference statements)

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“…Such analysisisac haracterization methodt hat has been increasingly applied to variousm aterials that presents memory properties, that is, ah ysteretic behavior,w hich is used to characterize ferroelectric [58] and SCO systems. [59][60][61][62][63][64][65][66] AF ORC is obtained by measuring the thermald ependence of the magnetic moment m(T, T a )b etween the reversal temperature T a and an extreme temperature at which the system is fully saturated (in one of the spin state being either HS or LS). Before each FORC registration, the sample is brought to the saturation.…”

Section: Forc Diagram Investigationmentioning

confidence: 99%

Two‐Step Spin Transition in a 1D Fe^II 1,2,4‐Triazole Chain Compound

Dîrtu

Schmit

Naik

et al. 2015

Chemistry A European J

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A thermochromic 1D spin crossover coordination (SCO) polymer [Fe(βAlatrz)3](BF4)2⋅2 H2O (1⋅2 H2O), whose precursor βAlatrz, (1,2,4-triazol-4-yl-propionate) has been tailored from a β-amino acid ester is investigated in detail by a set of superconducting quantum interference device (SQUID), (57)Fe Mössbauer, differential scanning calorimetry, infrared, and Raman measurements. An hysteretic abrupt two-step spin crossover (T1/2(↓) = 230 K and T1/2(↑) = 235 K, and T1/2(↓) = 172 K and T1/2(↑) = 188 K, respectively) is registered for the first time for a 1,2,4-triazole-based Fe(II) 1D coordination polymer. The two-step SCO configuration is observed in a 1:2 ratio of low-spin/high-spin in the intermediate phase for a 1D chain. The origin of the stepwise transition was attributed to a distribution of chains of different lengths in 1⋅2 H2O after First Order Reversal Curves (FORC) analyses. A detailed DFT analysis allowed us to propose the normal mode assignment of the Raman peaks in the low-spin and high-spin states of 1⋅2 H2O. Vibrational spectra of 1⋅2 H2O reveal that the BF4(-) anions and water molecules play no significant role on the vibrational properties of the [Fe(βAlatrz)3](2+) polymeric chains, although non-coordinated water molecules have a dramatic influence on the emergence of a step in the spin transition curve. The dehydrated material [Fe(βAlatrz)3](BF4)2 (1) reveals indeed a significantly different magnetic behavior with a one-step SCO which was also investigated.

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Section: Forc Diagram Investigationmentioning

confidence: 99%

Two‐Step Spin Transition in a 1D Fe^II 1,2,4‐Triazole Chain Compound

Dîrtu

Schmit

Naik

et al. 2015

Chemistry A European J

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“…It has already been pointed out that the elastic stress due to an external environment can be seen as a pressure, which can be assumed to be spin-state-dependent. [32] The direct consequence is a shift of the transition temperature of the SCO core (or the SCO shell). In the following, we note U def (n HS ) the HS-fraction-dependent deformation energy.…”

Section: Application To the Spin Transition In Coreshell Nanoparticlesmentioning

confidence: 99%

Control of the Phase Stability in Spin‐Crossover Core–Shell Nanoparticles through the Elastic Interface Energy

et al. 2017

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Size reduction leads to drastic changes in thermodynamic properties in spin-crossover (SCO) nano-objects in comparison with bulk materials. In particular, an important modification of the phase stability has been observed, reflected by a shift of the transition temperature. These changes are mostly attributed to the increasing role of surface properties at the nanoscale, especially the elastic properties, which play a key role in SCO phenomena. In this work, we propose a continuum mechanics approach to explore the possibility to tune the phase stability by controlling the interfacial elastic energy in core-shell nanoparticles with (semi-)coherent interface. To this aim, the pressure at the particle surface/interface is analytically

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“…Among several elastic models, the mechanoelastic model has been successfully adapted for characterizing the thermal hysteresis either in spin-crossover bulk, 12 microparticles 13 or nanoparticles, 12 by considering elastic interactions between the crystal and the environment, which may be described as a variable external pressure. 7 Recently, the size-dependent rigidity of nanoparticle was also explored in simulations as a possible cause for some experimental results on spin-crossover nanoparticle systems. 14 A sensitive method to characterize the hysteresis properties in spin-crossover materials is the first order reversal curves method.…”

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confidence: 99%

“…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.…”

mentioning

confidence: 99%

“…6 A similar behavior has been reported for Fe(phen) 2 (NCS) 2 spincrossover microparticles embedded in various surfactants. 7 In this paper, we simulate FORCs for spin-crossover compounds in the framework of the mechanoelastic model 12 and discuss them in terms of size and the strength of the elastic interactions. Even if the mechanoelastic model can reproduce qualitatively most of the special features of the spin-crossover nanoparticle hysteretic behavior, it cannot be used to calculate minor hysteresis loops (inside the hysteresis loop) as for a single particle it allows only the existence of two stable states.…”

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confidence: 99%

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

Stoleriu

Stancu

Chakraborty

et al. 2015

Journal of Applied Physics

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The recently obtained spin-crossover nanoparticles are possible candidates for applications in the recording media industry as materials for data storage, or as pressure and temperature sensors. For these applications, the intermolecular interactions and interactions between spin-crossover nanoparticles are extremely important, as they may be essential factors in triggering the transition between the two stable phases: the high-spin and low-spin ones. In order to find correlations between the distributions in size and interactions and the transition temperatures distribution, we apply the FORC (First Order Reversal Curves) method, using simulations based on a mechanoelastic model applied to 2D triangular lattices composed of molecules linked by springs and embedded in a surfactant. We consider two Gaussian distributions: one is the size of the nanoparticles and another is the elastic interactions between edge spin-crossover molecules and the surfactant molecules. In order to disentangle the kinetic and non-kinetic parts of the FORC distributions, we compare the results obtained for different temperature sweeping rates. We also show that the presence of few larger particles in a distribution centered around much smaller particles dramatically increases the hysteresis width

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Hysteretic behavior of Fe(phen)2(NCS)2 spin-transition microparticles vs. the environment: A huge reversible component resolved by first order reversal curves

Cited by 26 publications

References 30 publications

Two‐Step Spin Transition in a 1D Fe^II 1,2,4‐Triazole Chain Compound

Two‐Step Spin Transition in a 1D Fe^II 1,2,4‐Triazole Chain Compound

Control of the Phase Stability in Spin‐Crossover Core–Shell Nanoparticles through the Elastic Interface Energy

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

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Hysteretic behavior of Fe(phen)2(NCS)2 spin-transition microparticles vs. the environment: A huge reversible component resolved by first order reversal curves

Cited by 26 publications

References 30 publications

Two‐Step Spin Transition in a 1D FeII 1,2,4‐Triazole Chain Compound

Two‐Step Spin Transition in a 1D FeII 1,2,4‐Triazole Chain Compound

Control of the Phase Stability in Spin‐Crossover Core–Shell Nanoparticles through the Elastic Interface Energy

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

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Two‐Step Spin Transition in a 1D Fe^II 1,2,4‐Triazole Chain Compound

Two‐Step Spin Transition in a 1D Fe^II 1,2,4‐Triazole Chain Compound