Disordered magnetic system is a system composed of random distribution of magnetic moments,which exists as a regular form in paramagnetic materials,spin glasses,spin liquids,and magnetic nanoparticles.Although disordered magnetic systems have rapidly decaying fields similar to disordered charge systems,current researches mainly focus on the interaction of internal magnetic moments of disordered magnetic systems and the magnetic response of the systems under the external magnetic fields,and the mechanism of rapid decaying magnetic fields of disordered magnetic systems is not well understood.In this paper,one-dimensional and two-dimensional disordered magnetic moment system models are established for the external magnetic field distribution of the disordered magnetic moment,and the probability density function of the external magnetic flux density is derived.The results of the distribution function are compared with the simulation results of the disordered magnetic moment system of finite size.Based on the Ising model,Monte Carlo method was used to simulate the distribution of the magnetic moment inside the disordered magnetic system,and the influence of temperature on the probability density function of the external magnetic flux density was studied.Then,on the basis of one-dimensional and two-dimensional model,a three-dimensional disordered magnetic particle model is built.The method of molecular dynamics simulation of disordered magnetic particle distribution is used to explore the influencing factors of three-dimensional magnetic particle disorder.On the basis of temperature,the effects of interparticle friction and load on the disorder of magnetic particle system and the results of the competition between temperature,friction and load are discussed.The results show that the complete disorder of the magnetic moment guarantees the sharp attenuation of the magnetic field in the one-dimensional magnetic moment system,and the magnetic flux density in the one-dimensional system is finite.The external magnetic field attenuation of one-dimensional disordered magnetic system has three stages:single magnetic moment flux density,Gaussian distribution with variance approaching 0 and double exponential attenuation distribution.The two-dimensional results are similar to the one-dimensional results,but decay more slowly.In addition,according to the calculation results of Monte Carlo method,the disorder will increase with the increase of temperature,and there is a phase transition point.When it is lower than the phase transition point,the external magnetic flux density of the model is large.Near the phase transition point,the disorder increases rapidly,and the magnetic field decay is more rapid.Therefore,the disorder will lead to the magnetic field decay.Based on the simulation results of molecular dynamics,the increase of temperature will increase the disorder of three-dimensional magnetic particle system,and the influence factors such as friction and load will limit the influence of temperature on the disorder of magnetic particle system at low temperature,but they will increase the influence of temperature on the disorder of magnetic particle system at high temperature.This paper has important reference significance for the study of different types of disordered magnetic systems. |