Compensation effects and relation between the activation energy of spin transition and the hysteresis loop width for an iron(ii) complex

2016 ◽  
Vol 18 (25) ◽  
pp. 16690-16699 ◽  
Author(s):  
Mark B. Bushuev ◽  
Denis P. Pishchur ◽  
Elena B. Nikolaenkova ◽  
Viktor P. Krivopalov
Keyword(s):  
Hysteresis Loop ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Activation Barrier ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
High Activation ◽  
Activation Barriers ◽  
Spin Crossover Complexes ◽  
Hysteresis Loop Width

Wide thermal hysteresis loops for iron(ii) spin crossover complexes are associated with high activation barriers: the higher the activation barrier, the wider the hysteresis loop for a series of related spin crossover systems.

Dynamical control of the spin transition inside the thermal hysteresis loop of a spin-crossover single crystal

2016 ◽  
Vol 486 ◽  
pp. 187-191 ◽  
Author(s):  
Kamel Boukheddaden ◽  
Mouhamadou Sy ◽  
Miguel Paez-Espejo ◽  
Ahmed Slimani ◽  
François Varret
Keyword(s):  
Single Crystal ◽  
Hysteresis Loop ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Thermal Hysteresis Loop ◽  
Dynamical Control

scholarly journals Elastic Origin of the Unsymmetrical Thermal Hysteresis in Spin Crossover Materials: Evidence of Symmetry Breaking

Symmetry ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 828
Author(s):  
Mamadou Ndiaye ◽  
Nour El Islam Belmouri ◽  
Jorge Linares ◽  
Kamel Boukheddaden
Keyword(s):  
Symmetry Breaking ◽  
High Spin ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
Point Of View ◽  
Self Organization ◽  
Spin States ◽  
Heating And Cooling

The jungle of experimental behaviors of spin-crossover materials contains a tremendous number of unexpected behaviors, among which, the unsymmetrical hysteresis loops having different shapes on heating and cooling, that we often encounter in literature. Excluding an extra effect of crystallographic phase transitions, we study here these phenomena from the point of view of elastic modeling and we demonstrate that a simple model accounting for the bond lengths misfits between the high-spin and low-spin states is sufficient to describe the situation of unsymmetrical hysteresis showing plateaus at the transition only on cooling or on heating branches. The idea behind this effect relates to the existence of a discriminant elastic frustration in the lattice, which expresses only along the high-spin to low-spin transition or in the opposite side. The obtained two-step transitions showed characteristics of self-organization of the spin states under the form of stripes, which we explain as an emergence process of antagonist directional elastic interactions inside the lattice. The analysis of the spin state transformation inside the plateau on cooling in terms of two sublattices demonstrated that the elastic-driven self-organization of the spin states is accompanied with a symmetry breaking.

scholarly journals Design of Bistable Gold@Spin-Crossover Core-Shell Nanoparticles Showing Large Electrical Responses for the Spin Switching

2019 ◽  
Author(s):  
Ramón Torres-Cavanillas ◽  
Rocher Sanchis-Gual ◽  
Julien Dugay ◽  
Marc Coronado-Puchau ◽  
Dr. Mónica Giménez Marqués ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
Large Change ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Simple Protocol ◽  
Order Of Magnitude ◽  
Core Shell Nanoparticles

<p>A simple protocol to prepare core-shell gold@spin-crossover (Au@SCO) nanoparticles (NPs) based on the 1D spin-crossover [Fe(Htrz)<sub>2</sub>(trz)](BF<sub>4</sub>) coordination polymer is reported. The synthesis relies on a two-step approach consisting on a partial surface ligand substitution of the citrate-stabilized Au NPs followed by the controlled growth of a very thin layer of the SCO polymer. As a result, colloidally stable core@shell spherical NPs of 19 nm in size exhibiting a narrow distribution in sizes have been obtained, revealing a switchable SCOshell of <i>ca.</i>4 nm. Temperature-dependent charge transport measurements of an electrical device based on assemblies of these Au@SCO NPs display well-defined, reproducible and sharp thermal hysteresis loops in the conductance near room temperature. This device is characterized both, by a large change in conductance upon spin state switching, and a remarkable transition abruptness, as compared with other memory devices based on the pristine SCO NPs. As a result, the sensitivity of the device to the spin transition is dramatically improved, with values for the ON/OFF ratio which are an order of magnitude better than the best ones obtained in previous SCO devices.</p>

scholarly journals Design of Bistable Gold@Spin-Crossover Core-Shell Nanoparticles Showing Large Electrical Responses for the Spin Switching

2019 ◽  
Author(s):  
Ramón Torres-Cavanillas ◽  
Rocher Sanchis-Gual ◽  
Julien Dugay ◽  
Marc Coronado-Puchau ◽  
Dr. Mónica Giménez Marqués ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Spin Transition ◽  
Hysteresis Loops ◽  
Large Change ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Simple Protocol ◽  
Order Of Magnitude ◽  
Core Shell Nanoparticles

<p>A simple protocol to prepare core-shell gold@spin-crossover (Au@SCO) nanoparticles (NPs) based on the 1D spin-crossover [Fe(Htrz)<sub>2</sub>(trz)](BF<sub>4</sub>) coordination polymer is reported. The synthesis relies on a two-step approach consisting on a partial surface ligand substitution of the citrate-stabilized Au NPs followed by the controlled growth of a very thin layer of the SCO polymer. As a result, colloidally stable core@shell spherical NPs of 19 nm in size exhibiting a narrow distribution in sizes have been obtained, revealing a switchable SCOshell of <i>ca.</i>4 nm. Temperature-dependent charge transport measurements of an electrical device based on assemblies of these Au@SCO NPs display well-defined, reproducible and sharp thermal hysteresis loops in the conductance near room temperature. This device is characterized both, by a large change in conductance upon spin state switching, and a remarkable transition abruptness, as compared with other memory devices based on the pristine SCO NPs. As a result, the sensitivity of the device to the spin transition is dramatically improved, with values for the ON/OFF ratio which are an order of magnitude better than the best ones obtained in previous SCO devices.</p>

A mononuclear five-coordinate Co(ii) single molecule magnet with a spin crossover between the S = 1/2 and 3/2 states

2018 ◽  
Vol 47 (46) ◽  
pp. 16596-16602 ◽  
Author(s):  
Lei Chen ◽  
Jingbo Song ◽  
Wen Zhao ◽  
Gangji Yi ◽  
Zhikuan Zhou ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Single Molecule ◽  
Magnetic Relaxation ◽  
Spin Crossover ◽  
Spin Transition ◽  
Single Molecule Magnet ◽  
Pyramidal Geometry ◽  
Mononuclear Cobalt ◽  
Slow Magnetic Relaxation ◽  
Square Pyramidal Geometry

A mononuclear cobalt(ii) complex with square pyramidal geometry displays a spin transition with a small hysteresis loop and slow magnetic relaxation.

Bidirectional photo-switching of the spin state of iron(II) ions in a triazol based spin crossover complex within the thermal hysteresis loop

2009 ◽  
Vol 477 (1-3) ◽  
pp. 156-159 ◽  
Author(s):  
Nawel Ould Moussa ◽  
Denis Ostrovskii ◽  
Victor Martinez Garcia ◽  
Gábor Molnár ◽  
Koichiro Tanaka ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Spin State ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Thermal Hysteresis Loop

Amphiphilic iron(ii) spin crossover coordination polymers: crystal structures and phase transition properties

2019 ◽  
Vol 7 (5) ◽  
pp. 1151-1163 ◽  
Author(s):  
Johannes Weihermüller ◽  
Stephan Schlamp ◽  
Wolfgang Milius ◽  
Florian Puchtler ◽  
Josef Breu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Crystal Structures ◽  
Coordination Polymers ◽  
Spin Crossover ◽  
Spin Transition ◽  
Spin Crossover Complexes ◽  
Platelet Formation

A cooperative spin transition and thin platelet formation is observed for 1D coordination polymers of amphiphilic iron(ii) spin crossover complexes.

scholarly journals Evidence of Photo-Thermal Effects on the First-Order Thermo-Induced Spin Transition of [{Fe(NCSe)(py)2}2(m-bpypz)] Spin-Crossover Material

2019 ◽  
Vol 5 (2) ◽  
pp. 21 ◽  
Author(s):  
Kamel Boukheddaden ◽  
Houcem Fourati ◽  
Yogendra Singh ◽  
Guillaume Chastanet
Keyword(s):  
Thermal Effects ◽  
Spin Crossover ◽  
Evolution Equations ◽  
Thermal Hysteresis ◽  
Magnetic Measurements ◽  
Equations Of Motion ◽  
Spin Transition ◽  
Thermal Bath ◽  
Trapping Region ◽  
First Order

We have investigated by means of optical microscopy and magnetic measurements the first-order thermal spin transition of the [{Fe(NCSe)(py)2}2(m-bpypz)] spin-crossover compound under various shining intensities, far from the light-induced spin-state trapping region. We found evidence of photo-heating effects on the thermally-induced hysteretic response of this spin-crossover material, thus causing the shift of the thermal hysteresis to lower temperature regions. The experimental results are discussed in terms of the apparent crystal temperature and are analyzed theoretically using two evolution equations of motion, written on the high-spin (HS) fraction and heat balance between the crystal and the thermal bath. A very good qualitative agreement was found between experiment and theory in the stationary regime, explaining the experimental observations well and identifying the key factors governing these photo-thermal effects.

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