scholarly journals Spin crossover with thermal hysteresis: practicalities and lessons learnt

2015 ◽  
Vol 44 (10) ◽  
pp. 2880-2892 ◽  
Author(s):  
Sally Brooker
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis ◽  
Magnetic Data ◽  
Lessons Learnt ◽  
Memory Applications

Memory applications of spin crossover require bistability: magnetic data must be appropriately collected and reported, and consideration given to lifetimes.

scholarly journals Hysteretic Thermal Spin-Crossover and Symmetry Breaking in Heteroleptic Fe(II) Complexes Using Alkyl Chain Substituted 2,2’-Dipyridylamine Ligands

2019 ◽  
Author(s):  
Blaise Geoghegan ◽  
Wasinee Phonsri ◽  
Peter Horton ◽  
James Orton ◽  
Simon Coles ◽  
...  
Keyword(s):  
Phase Transition ◽  
Spin Crossover ◽  
Alkyl Chain ◽  
Thermal Hysteresis ◽  
Variable Temperature ◽  
Spin Transition ◽  
Magnetic Data ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Bond Lengths

The alkyl chain carrying ligands N,N-di(pyridin-2-yl)butanamide (LC4) and N,N-di(pyridin-2-yl)decanamide (LC10) were combined with NCS- co-ligands to form the neutral heteroleptic Fe(II) complexes trans-[FeII(LC4)2(NCS)2] (1C4) and trans [FeII(LC10)2(NCS)2] (1C10). Variable temperature crystallographic studies revealed that 1C4 is in the orthorhombic space group Pna21 between 85-200 K whereas 1C10 is in the monoclinic space group P21/c between 85-105 K before undergoing a crystallographic phase transition to the triclinic space group P1􀴤 by 140 K. The average Fe-N bond lengths suggest that at 85 K 1C4 contains LS Fe(II) centres; However, the ca. 0.18 Å increase in the average Fe-N bond lengths between 85 and 120 K suggests a spin-transition occurs within this temperature interval and the HS state is predominant beyond this. 1C10 contains LS Fe(II) centres between 85 and 105 K. Upon warming from 105 to 140 K the average Fe-N bond lengths increase by ca. 0.19 Å, which suggests that a spin-transition to the HS accompanies the P21/c to P1􀴤 crystallographic phase transition. Solid-state magnetic susceptibility measurements showed that 1C4 undergoes semi-abrupt spin-crossover with T1/2 = 127.5 K and a thermal hysteresis of ca. 13 K whereas, 1C10 undergoes an abrupt spin-crossover with T1/2 = 119.0 K, and is also accompanied by thermal hysteresis of ca. 4 K. The crystallographic and magnetic data show that the length of the complex’s alkyl chain substituents can have a large impact on the structure of the crystal lattice as well as a subtle effect on the T1/2 value for thermal spin-crossover.

scholarly journals Hysteretic Thermal Spin-Crossover and Symmetry Breaking in Heteroleptic Fe(II) Complexes Using Alkyl Chain Substituted 2,2’-Dipyridylamine Ligands

2019 ◽  
Author(s):  
Blaise Geoghegan ◽  
Wasinee Phonsri ◽  
Peter Horton ◽  
James Orton ◽  
Simon Coles ◽  
...  
Keyword(s):  
Phase Transition ◽  
Spin Crossover ◽  
Alkyl Chain ◽  
Thermal Hysteresis ◽  
Variable Temperature ◽  
Spin Transition ◽  
Magnetic Data ◽  
Monoclinic Space Group ◽  
Space Group ◽  
Bond Lengths

The alkyl chain carrying ligands N,N-di(pyridin-2-yl)butanamide (LC4) and N,N-di(pyridin-2-yl)decanamide (LC10) were combined with NCS- co-ligands to form the neutral heteroleptic Fe(II) complexes trans-[FeII(LC4)2(NCS)2] (1C4) and trans [FeII(LC10)2(NCS)2] (1C10). Variable temperature crystallographic studies revealed that 1C4 is in the orthorhombic space group Pna21 between 85-200 K whereas 1C10 is in the monoclinic space group P21/c between 85-105 K before undergoing a crystallographic phase transition to the triclinic space group P1􀴤 by 140 K. The average Fe-N bond lengths suggest that at 85 K 1C4 contains LS Fe(II) centres; However, the ca. 0.18 Å increase in the average Fe-N bond lengths between 85 and 120 K suggests a spin-transition occurs within this temperature interval and the HS state is predominant beyond this. 1C10 contains LS Fe(II) centres between 85 and 105 K. Upon warming from 105 to 140 K the average Fe-N bond lengths increase by ca. 0.19 Å, which suggests that a spin-transition to the HS accompanies the P21/c to P1􀴤 crystallographic phase transition. Solid-state magnetic susceptibility measurements showed that 1C4 undergoes semi-abrupt spin-crossover with T1/2 = 127.5 K and a thermal hysteresis of ca. 13 K whereas, 1C10 undergoes an abrupt spin-crossover with T1/2 = 119.0 K, and is also accompanied by thermal hysteresis of ca. 4 K. The crystallographic and magnetic data show that the length of the complex’s alkyl chain substituents can have a large impact on the structure of the crystal lattice as well as a subtle effect on the T1/2 value for thermal 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).

Tuning Size and Thermal Hysteresis in Bistable Spin Crossover Nanoparticles

2010 ◽  
Vol 49 (12) ◽  
pp. 5706-5714 ◽  
Author(s):  
José Ramón Galán-Mascarós ◽  
Eugenio Coronado ◽  
Alicia Forment-Aliaga ◽  
María Monrabal-Capilla ◽  
Elena Pinilla-Cienfuegos ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis

First-order reversal curves analysis of rate-dependent hysteresis: The example of light-induced thermal hysteresis in a spin-crossover solid

2005 ◽  
Vol 72 (5) ◽  
Author(s):  
Cristian Enachescu ◽  
Radu Tanasa ◽  
Alexandru Stancu ◽  
Francois Varret ◽  
Jorge Linares ◽  
...  
Keyword(s):  
Spin Crossover ◽  
Thermal Hysteresis ◽  
First Order ◽  
Rate Dependent

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

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.

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