Spatiotemporal Investigations on Light-Driven High-Spin–Low-Spin Interface Dynamics in the Thermal Hysteresis Region of a Spin-Crossover Single Crystal

2018 ◽  
Vol 122 (36) ◽  
pp. 20952-20962 ◽  
Author(s):  
Mouhamadou Sy ◽  
Rachid Traiche ◽  
Houcem Fourati ◽  
Yogendra Singh ◽  
François Varret ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Spin ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Interface Dynamics

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.

Structure-Driven Orientation of the High-Spin-Low-Spin Interface in a Spin-Crossover Single Crystal

2014 ◽  
Vol 126 (29) ◽  
pp. 7669-7672 ◽  
Author(s):  
Mouhamadou Sy ◽  
François Varret ◽  
Kamel Boukheddaden ◽  
Guillaume Bouchez ◽  
Jérôme Marrot ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Spin ◽  
Spin Crossover

scholarly journals Ultrafast spin crossover in a single crystal

2019 ◽  
Vol 205 ◽  
pp. 07009
Author(s):  
Ryan L. Field ◽  
Lai Chung Liu ◽  
Yifeng Jiang ◽  
Wojciech Gawelda ◽  
Cheng Lu ◽  
...  
Keyword(s):  
Electron Diffraction ◽  
Single Crystal ◽  
High Spin ◽  
Spin Crossover ◽  
Femtosecond Spectroscopy ◽  
Show Evidence ◽  
Spin Lifetime ◽  
Vibrational Cooling

Femtosecond spectroscopy and electron diffraction are used to characterize spin crossover in single crystal iron(II)-tris(bipyridine)-bis(hexafluorophosphate). The high-spin lifetime is reduced compared to in solution. Preliminary electron diffraction experiments show evidence of ultrafast Fe-N bond elongation associated with spin crossover and the subsequent molecular reorganization resulting from vibrational cooling.

Spatiotemporal Observation and Modeling of Remarkable Temperature Scan Rate Effects on the Thermal Hysteresis in a Spin-Crossover Single Crystal

2017 ◽  
Vol 121 (21) ◽  
pp. 11700-11708 ◽  
Author(s):  
Rachid Traiche ◽  
Mouhamadou Sy ◽  
Hassane Oubouchou ◽  
Guillaume Bouchez ◽  
François Varret ◽  
...  
Keyword(s):  
Single Crystal ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Rate Effects ◽  
Scan Rate

scholarly journals High-Temperature Cooperative Spin Crossover Transitions and Single-Crystal Reflection Spectra of [FeIII(qsal)2](CH3OSO3) and Related Compounds

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 81 ◽  
Author(s):  
Kazuyuki Takahashi ◽  
Kaoru Yamamoto ◽  
Takashi Yamamoto ◽  
Yasuaki Einaga ◽  
Yoshihito Shiota ◽  
...  
Keyword(s):  
High Temperature ◽  
Single Crystal ◽  
Crystal Structures ◽  
Optical Conductivity ◽  
Density Functional ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Reflection Spectra ◽  
Absorption Bands ◽  
Conductivity Spectra

New Fe(III) compounds from qsal ligand, [Fe(qsal)2](CH3OSO3) (1) and [Fe(qsal)2](CH3SO3)·CH3OH (3), along with known compound, [Fe(qsal)2](CF3SO3) (2), were obtained as large well-shaped crystals (Hqsal = N-(8-quinolyl)salicylaldimine). The compounds 1 and 2 were in the low-spin (LS) state at 300 K and exhibited a cooperative spin crossover (SCO) transition with a thermal hysteresis loop at higher temperatures, whereas 3 was in the high-spin (HS) state below 300 K. The optical conductivity spectra for 1 and 3 were calculated from the single-crystal reflection spectra, which were, to the best of our knowledge, the first optical conductivity spectra of SCO compounds. The absorption bands for the LS and HS [Fe(qsal)2] cations were assigned by time-dependent density functional theory calculations. The crystal structures of 1 and 2 consisted of a common one-dimensional (1D) array of the [Fe(qsal)2] cation, whereas that of 3 had an unusual 1D arrangement by π-stacking interactions which has never been reported. The crystal structures in the high-temperature phases for 1 and 2 indicate that large structural changes were triggered by the motion of counter anions. The comparison of the crystal structures of the known [Fe(qsal)2] compounds suggests the significant role of a large non-spherical counter-anion or solvate molecule for the total lattice energy gain in the crystal of a charged complex.

Structure-Driven Orientation of the High-Spin-Low-Spin Interface in a Spin-Crossover Single Crystal

2014 ◽  
Vol 53 (29) ◽  
pp. 7539-7542 ◽  
Author(s):  
Mouhamadou Sy ◽  
François Varret ◽  
Kamel Boukheddaden ◽  
Guillaume Bouchez ◽  
Jérôme Marrot ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Spin ◽  
Spin Crossover

Spin-crossover in an iron(iii) complex showing a broad thermal hysteresis

2021 ◽  
Author(s):  
Cyril Rajnák ◽  
Romana Mičová ◽  
Ján Moncoľ ◽  
Ľubor Dlháň ◽  
Christoph Krüger ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligand ◽  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Mononuclear Complex ◽  
Hysteresis Width ◽  
Thermally Induced

A pentadentate Schiff-base ligand 3,5Cl-L2− and NCSe− form a iron(iii) mononuclear complex [Fe(3,5Cl-L)(NCSe)], which shows a thermally induced spin crossover with a broad hysteresis width of 24 K between 123 K (warming) and 99 K (cooling).

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