Numerical Calculation Of Magnetic Properties For Nanowires

In this thesis, the magnetic properties of nanowires and their arraies have been studied with numerical methods. The purpose is to investigate the magnetization reversal of nanowires by studying the macroscopical quantity. The main contents of this paper are arranged as follows:Firstly, we present the essential conception, phylogeny, physical characters of nanomaterial, the phylogeny and research actuality of magnetic nanowire array. Following, we mostly present the basal theory involved in this paper. It included magnetic hysteresis loops, the energy terms considered in the simulation and the magnetic reversal mechanism. Afterward, we chiefly introduce Monte Carlo method and fast Fourier transformation and micromagnetism (FFTM).Secondly, based on Monte Carlo method, we investigated magnetic hysteresis loops, coercivity as functions of temperature and angle, switching field as a function of angle, and the magnetic reversal mechanism. The simulated results are consistent with the experimental data.On one hand, using two kinds of discretization cells regular global-shaped and regular cubic-shaped as minimum element, the magnetic properties of Fe nanowire were studied. The simulation results reveal as follows:①The simulated results using the global-shaped discretization cell have more accurate results which is compared to the experimental result than those using the cubic-shaped discretization cell does.②The coercivity of the magnetic nanowire decreases with increasing nanowire diameter. This change trend is agreement with the experimental fact.③The T^-α power-law describes the H_C-T curves well.On the other hand, based on Monte Carlo method, we simulate the magnetization curves of various single Co nanowires at room temperature. The simulated switching field as a function of angles (θ) between the field and wire axis fits well with the experimental data. Correspondingly, the coercivity as a function of angles is presented. The simulated results indicate that (1) the coercivity as a function of angles is found to depend on the...