Study Of The Physical Properties Of Fullerene-Like Structures By Monte Carlo Method

At present,materials with fullerene-like structure have become the hot spot of composite materials because of their great improvement in chemical and physical properties,and they have great application prospects in magnetic devices and magnetic refrigerating materials.In this study,the magnetic and thermodynamic properties of the Fullerene-like structures X_nY_60-n,X₂₀@single-walled nanotubes and Dy Sc₂N@C₈₀are studied by Monte Carlo method based on the Ising model.Firstly,the effects of exchange coupling,lattice ratio and external magnetic field on the magnetization,susceptibility,specific heat,internal energy,magnetic entropy change and adiabatic temperature change of the system are studied in X_nY_60-nstructure.The system with large spin has higher magnetic cooling efficiency,and the large exchange coupling can greatly limit the magnetic entropy change of X_nY_60-n.Secondly,the compensation behavior of the ferrimagnetic X₂₀@single-walled nanotubes is investigated.The magnetization of the system shows the P,Q and N-type curves predicted by Néel theory.It is found that the increase of exchange coupling between core and shell makes the system phase transition into two phases.X₂₀@single-walled nanotubes in ferromagnetic configuration have good magnetocaloric properties,and the increase of exchange coupling is not conducive to the increase of entropy change,but it can make the range of entropy increase wider.The effects of anisotropy and other parameters on the magnetocaloric properties of X₂₀@single-walled nanotubes are revealed.Finally,the particle swarm optimization algorithm and Monte Carlo method are combined to calculate the specific simulation parameters of the Ising model based on the Curie temperature simulation of the materials.We combine with experimental results more accurately and give a physical mechanism in accordance with the explanation to preview of all aspects of the properties of the material more accurately.Through detailed calculation,screening and analysis,the magnetic exchange coupling J=0.0000759e V and the anisotropy D=0.01881e V of the cubic crystal Dy Sc₂N@C₈₀are obtained.The order of magnitude of D is much greater than that of J,which indicates that the magnetic anisotropy in the molecular crystal is the main factor to affect its magnetic properties.The influence of the external magnetic field on the magnetic properties of the system and the hysteresis phenomenon are studied under the effect of this parameter.This study reveals more physical and chemical properties of fullerenes and plays a guiding role in the research and development of fullerene-like materials.