Ising-Like Model of Nanosize Spin-Crossover Molecular Crystals
157
premature saturation with smaller magnetization value for HS state and greater one
for LS configuration in contrast to the completely ferromagnetic system. Physically,
it is explained by the antiferromagnetic ordering of molecules on the surface that can
impact the ordering of the next layer. The last plays a role of interface between the
surface and the bulk parts of the nanocrystal system.
The determination of critical particle size necessary to preserve the first-order
transition in SCO materials is imperative because bistability depends on the collective behavior of molecules in the SCO lattice. The critical temperature of the spin
transition shifts toward equilibrium temperature as the nanocrystal size approaches
to the critical one, where the hysteresis width vanishes.
It was an established good agreement between the obtained numerical results
and the experimental studies. Most of the experimentally obtained hysteresis loops
for spin-crossover compounds, in which the shifting of critical temperatures, the
incompleteness of transitions, and the vanishing of hysteresis with decreasing of
system size are observed, might be explained within the system with the change in
cooperativity from the surface to the bulk of the lattice, taking into account the antiand ferromagnetic nature of surface’s sites.
It is expected that obtained results will be useful for designing new electronic
devices based on spin-crossover compounds, including sensors, data storage, and
recording systems with much better characteristics. Understanding the role of size
effects in spin-crossover materials with statistical fluctuations may improve the functioning of any system based on molecular materials with spin transition.
Acknowledgements The research of A.M. was partly supported by the project No.2015/19/B/
ST2/01028 financed by National Science Centre (Poland).
References
1. Atkins P, Overton T, Rourke JP, Weller MT, Armstrong FA (2010) Shriver and Atkins inorganic
chemistry. Oxford University Press, New York
2. Halcrow MA (ed) (2013) Spin-crossover materials: properties and applications. Wiley, Chichester
3. Gudyma Iu, Enachescu C, Maksymov A (2015) Kinetics of nonequilibrium transition in spincrossover compounds. In: Nanocomposites, Nanophotonics, Nanobiotechnology, and Applications, Springer, pp 375–401
4. Kumar KS, Ruben M (2017) Emerging trends in spin crossover (SCO) based functional materials and devices. Coordin Chem Rev 346:176–205
5. Iasco O, Boillot M-L, Bellec A, Guillot R, Riviere E, Mazerat S, Nowak S, Morineau D,
Brosseau A, Miserque F (2017) The disentangling of hysteretic spin transition, polymorphism
and metastability in bistable thin films formed by sublimation of bis (scorpionate) Fe (II)
molecules. J Mater Chem C 5(42):11067–11075
6. Molnár G, Rat S, Salmon L, Nicolazzi W, Bousseksou A (2018) Spin crossover nanomaterials:
from fundamental concepts to devices. Adv Mater 30(5):1703862
7. Simon-Yarza T, Mielcarek A, Couvreur P, Serre C (2018) Nanoparticles of metal-organic
frameworks: On the road to in vivo efficacy in biomedicine. Adv Mater 2018:1707365
8. Salmon L, Catala L (2018) Spin-crossover nanoparticles and nanocomposite materials.
Comptes Rendus Chimie 21(12):1230–1269
157
premature saturation with smaller magnetization value for HS state and greater one
for LS configuration in contrast to the completely ferromagnetic system. Physically,
it is explained by the antiferromagnetic ordering of molecules on the surface that can
impact the ordering of the next layer. The last plays a role of interface between the
surface and the bulk parts of the nanocrystal system.
The determination of critical particle size necessary to preserve the first-order
transition in SCO materials is imperative because bistability depends on the collective behavior of molecules in the SCO lattice. The critical temperature of the spin
transition shifts toward equilibrium temperature as the nanocrystal size approaches
to the critical one, where the hysteresis width vanishes.
It was an established good agreement between the obtained numerical results
and the experimental studies. Most of the experimentally obtained hysteresis loops
for spin-crossover compounds, in which the shifting of critical temperatures, the
incompleteness of transitions, and the vanishing of hysteresis with decreasing of
system size are observed, might be explained within the system with the change in
cooperativity from the surface to the bulk of the lattice, taking into account the antiand ferromagnetic nature of surface’s sites.
It is expected that obtained results will be useful for designing new electronic
devices based on spin-crossover compounds, including sensors, data storage, and
recording systems with much better characteristics. Understanding the role of size
effects in spin-crossover materials with statistical fluctuations may improve the functioning of any system based on molecular materials with spin transition.
Acknowledgements The research of A.M. was partly supported by the project No.2015/19/B/
ST2/01028 financed by National Science Centre (Poland).
References
1. Atkins P, Overton T, Rourke JP, Weller MT, Armstrong FA (2010) Shriver and Atkins inorganic
chemistry. Oxford University Press, New York
2. Halcrow MA (ed) (2013) Spin-crossover materials: properties and applications. Wiley, Chichester
3. Gudyma Iu, Enachescu C, Maksymov A (2015) Kinetics of nonequilibrium transition in spincrossover compounds. In: Nanocomposites, Nanophotonics, Nanobiotechnology, and Applications, Springer, pp 375–401
4. Kumar KS, Ruben M (2017) Emerging trends in spin crossover (SCO) based functional materials and devices. Coordin Chem Rev 346:176–205
5. Iasco O, Boillot M-L, Bellec A, Guillot R, Riviere E, Mazerat S, Nowak S, Morineau D,
Brosseau A, Miserque F (2017) The disentangling of hysteretic spin transition, polymorphism
and metastability in bistable thin films formed by sublimation of bis (scorpionate) Fe (II)
molecules. J Mater Chem C 5(42):11067–11075
6. Molnár G, Rat S, Salmon L, Nicolazzi W, Bousseksou A (2018) Spin crossover nanomaterials:
from fundamental concepts to devices. Adv Mater 30(5):1703862
7. Simon-Yarza T, Mielcarek A, Couvreur P, Serre C (2018) Nanoparticles of metal-organic
frameworks: On the road to in vivo efficacy in biomedicine. Adv Mater 2018:1707365
8. Salmon L, Catala L (2018) Spin-crossover nanoparticles and nanocomposite materials.
Comptes Rendus Chimie 21(12):1230–1269