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Study of pressure influence on thermal transition in spin-crossover nanomaterials.

Gudyma IV, Maksymov AIu, Ivashko VV - Nanoscale Res Lett (2014)

Bottom Line: The thermal transition accompanied by the variation of the molecular volume in nanoparticles of spin-crossover materials has been studied on the basis of microscopic Ising-like model solved using Monte Carlo methods.For considered model, we examined the spin-crossover phenomenon with applied hydrostatic pressure and thus was shown the possibility to shift transition temperature toward its room value.The obtained results of numerical simulations are in agreement with the experimental ones.

View Article: PubMed Central - PubMed

Affiliation: Department of General Physics, Chernivtsi National University, Kotsjubynskyi Str. 2, 58012, Chernivtsi, Ukraine, yugudyma@gmail.com.

ABSTRACT
The thermal transition accompanied by the variation of the molecular volume in nanoparticles of spin-crossover materials has been studied on the basis of microscopic Ising-like model solved using Monte Carlo methods. For considered model, we examined the spin-crossover phenomenon with applied hydrostatic pressure and thus was shown the possibility to shift transition temperature toward its room value. The obtained results of numerical simulations are in agreement with the experimental ones.

No MeSH data available.


The changes of transition temperatures during cooling and heating processes with increase ofpΔVand interaction constantJ.
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Fig3: The changes of transition temperatures during cooling and heating processes with increase ofpΔVand interaction constantJ.

Mentions: In order to characterize the changes of hysteresis width for different interaction constant and pressure, we have built the 3D plot of transition temperatures during cooling and heating process Tdown and Tup. These temperatures are defined as equilibrium temperatures at which the fraction of HS molecules takes the value nHS=0.5. The obtained results are shown in Figure 3. Here, the red balls indicate the values of transition temperature during cooling Tdown, and green balls correspond to transition temperatures during heating Tup. If it comes to hysteresis width, it can be judged from the difference between Tup and Tdown for certain values of pressure and interaction constant. According to Figure 3, the hysteresis width decreases with a slight asymmetry with pressure increasing. The similar behavior is shown with decreasing interaction constant. In this plot, it is interesting to distinguish the behavior of transition temperature for which hysteresis collapses. The blue line in J−pΔV plane is the projection of edge of plane with equal values of Tdown and Tup. For the values of J larger than ones from the blue line, the second-order phase transition is observed. As we can see from Figure 3, the dependence between the values of pΔV and J for which hysteresis collapses is approximately linear.Figure 3


Study of pressure influence on thermal transition in spin-crossover nanomaterials.

Gudyma IV, Maksymov AIu, Ivashko VV - Nanoscale Res Lett (2014)

The changes of transition temperatures during cooling and heating processes with increase ofpΔVand interaction constantJ.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494018&req=5

Fig3: The changes of transition temperatures during cooling and heating processes with increase ofpΔVand interaction constantJ.
Mentions: In order to characterize the changes of hysteresis width for different interaction constant and pressure, we have built the 3D plot of transition temperatures during cooling and heating process Tdown and Tup. These temperatures are defined as equilibrium temperatures at which the fraction of HS molecules takes the value nHS=0.5. The obtained results are shown in Figure 3. Here, the red balls indicate the values of transition temperature during cooling Tdown, and green balls correspond to transition temperatures during heating Tup. If it comes to hysteresis width, it can be judged from the difference between Tup and Tdown for certain values of pressure and interaction constant. According to Figure 3, the hysteresis width decreases with a slight asymmetry with pressure increasing. The similar behavior is shown with decreasing interaction constant. In this plot, it is interesting to distinguish the behavior of transition temperature for which hysteresis collapses. The blue line in J−pΔV plane is the projection of edge of plane with equal values of Tdown and Tup. For the values of J larger than ones from the blue line, the second-order phase transition is observed. As we can see from Figure 3, the dependence between the values of pΔV and J for which hysteresis collapses is approximately linear.Figure 3

Bottom Line: The thermal transition accompanied by the variation of the molecular volume in nanoparticles of spin-crossover materials has been studied on the basis of microscopic Ising-like model solved using Monte Carlo methods.For considered model, we examined the spin-crossover phenomenon with applied hydrostatic pressure and thus was shown the possibility to shift transition temperature toward its room value.The obtained results of numerical simulations are in agreement with the experimental ones.

View Article: PubMed Central - PubMed

Affiliation: Department of General Physics, Chernivtsi National University, Kotsjubynskyi Str. 2, 58012, Chernivtsi, Ukraine, yugudyma@gmail.com.

ABSTRACT
The thermal transition accompanied by the variation of the molecular volume in nanoparticles of spin-crossover materials has been studied on the basis of microscopic Ising-like model solved using Monte Carlo methods. For considered model, we examined the spin-crossover phenomenon with applied hydrostatic pressure and thus was shown the possibility to shift transition temperature toward its room value. The obtained results of numerical simulations are in agreement with the experimental ones.

No MeSH data available.