Study In Spin Wave Band Structure Of Two Dimentional Magnetic Crystal Slab

Magnetic crystal is an artificial micro structure composite material. The main characteristic of magnetic crystals is that the spin wave propagating in magnetic crystal can be controlled by the periodic structure. As an important step of actual use in magnetic crystal the magnetic crystal slab has been in a hot research.The magnetic crystal slab eigen equation in two kinds of cases that the external magnetic field was parallel and perpendicular to the magnetic crystal slab is derived from the improved plan wave expansion method and a method of processing the surface boundary effect called near uniform mode. I also numerically calculated band structure of magnetic structure in two cases.According to the results of numerical calculations obtain following consequences. First, planar two-dimensional bi-component magnetic crystals can form a Completed band gap, when the external magnetic field perpendicular to the magnetic crystal slab. Second, when the external magnetic field is perpendicular to the magnetic crystal we found that the thickness of magnetic crystal and the strength of external magnetic field all can control the band gap wide.