Study On Physical Properties Of Magnetic Multilayer Films By Monte Carlo Method

With the rapid development of science technology,the research and the application of layered magnetic materials have been concerned.Among them,there are the compensation temperatures in the ferrimagnetic materials,which have important applications in thermo-magnetic recording.At the same time,the method and technology synthetic film material have been diversified,such as the sol-gel method,the pulsed laser deposition,the metal organic vapor deposition,molecular beam epitaxy,magnetron sputtering,etc.In addition,with the breakthrough of theory and the practical application of science,the magnetic multilayer materials are entering a rapid-growth period.In the paper,we have set up a double-layer ferrimagnetic mixed spin(1/2,1)Ising model,triple-layer mixed ferrimagnetic spin(1/2,1,3/2)Ising model and triple-layer ferromagnetic mixed spin(1/2,1,3/2)Ising model for the layered mixed-spin magnetic multilayers.We have studied the magnetic and thermodynamic properties by Monte Carlo simulation for these three systems,and the effects of temperature,exchange coupling,film thickness and concentration of magnetic atomics on the magnetization,the susceptibility,the internal energy,the specific heat,the compensation and the critical behaviors of the system have been discussed in detail.The effects of the layer thickness and the exchange coupling on the magnetic and thermodynamic properties of the ferrimagnetic double-layer mixed spin(1/2,1)Ising model were studied,and we have focused on compensation and transition behaviors.The results show that with the exchange coupling Jbb increasing,the transition and the compensation temperatures of the system are increasing,and the smaller the Jbb is,the easier the compensation behavior is.The competition between temperature and exchange coupling leads to the N type,Q type and P type curves as classified in the Néel theory of the ferrimagnetic material.The interlayer exchange coupling Jab has little effect on the transition and the compensation temperatures.With the increasing of the layer thickness L,the transition temperature increases first and then remains unchanged.When L is smaller,the compensation temperature changes more obviously.The effects of the layer thickness,the exchange coupling and the magnetic atomicconcentration on the magnetic and thermodynamic properties of triple-layer ferrimagnetic mixed spin(1/2,1,3/2)Ising model are studied,and we have focused on the compensation and the transition behaviors.With the increasing Jbb,the compensation temperature does not change and the transition temperature increases.The larger the Jcc is,the more difficult for the compensation temperature to appear in this system.The results show that the thickness L increases,the compensation temperature is constant,and the transition temperature increases.With the increasing of the sublattice thickness Lb,the transition temperature increases,and the compensation temperature disappears,indicating that the larger the Lb is,the more difficult for the compensation temperature to appear.When the sublattice thickness Lc increases,the transition temperature is constant,and the compensation temperature increases first and then remains unchanged.Changing the magnetic atomic concentration P,we find that the system has double compensation points in the phase diagram.As a comparison with those results of the effective-field theory(EFT),we also have studied the transition behavior of the triple-layer ferromagnetic mixed-spin(1/2,1,3/2)Ising model,an excellent agreement has been achieved between us.Furthermore,the transition temperature of the system increases with the increase of L,Lc and Jcc.But when we increase the Lb and Jbb,the transition temperature of the system is almost no change.