The Effects Of Surface Roughness Upon Magnetic Films' Magnetism

In this thesis,we perform Monte Carlo simulations to study the effects of surface roughness upon magnetic properties of the films.The main contents of this paper are arranged as follows:1.The essential conception,sort and physical characters of nanostructure magnetic materials are introduced in brief.Following,the basal theory and the Monte Carlo method are introdued.2.Base on the Monte Carlo simulation,the effects of surface roughness upon ferromagnetic films and diluted films are studied,respectively.It is found:(1)The surface roughness of the films is decided by the ratio of atoms filling in the surface,and the surface roughnessγneed to be defined asγ+orγ-according to the various structures of the films.(2)For the ferromagnetic films,the relationships of magnetic properties withγ+ andγ.are not consistent.This is because that,the coordination number has correlation with surface roughness and it influence significantly the magnetic properties of the films.(3)For the diluted films,the coercivity H_c as a function of the surface roughnessγfor large antiferromagnetic atom ratio is strong different from that for large ferromagnetic atom ratio.The coordination(?)and ferromagnetic/antiferromagnetic mixed ratio X₀ influence clearly the coercivity H_c.3.We also perform the Monte Carlo simulation to study the effects of surface roughness upon free ferromagnetic films.It's noted that the effects of surface roughness upon the magnetic properties of free and coated ferromagnetic films exist clear differences,which is due to the enhancing magnetization at the surface of the free films.