Research On Band Gap Structure Of One-Dimensional Function Magnonic Crystal

In recent years,with the advancement of nanotechnology and more in-depth understanding of mesoscopic world,artificial composite material superlattice,as an important branch of crystallography,has been received widespread attention.In a spatial periodic way,superlattice,whose structure and size could be adjusted and generated many unusual physical properties,is composed of two or more sorts of material with different physical and chemical properties.Typically,the photonic crystal and phononic crystal can tune the photons and phonons propagatin inside them respectively,and the characteristic of band gap structure made them widely applied in the field of information technology.Magnonic Crystals(MCs)is a new type of artificial composite material which was inspired from the invention of the photonic crystal and phononic crystal.Compared with photons and phonons,the spin wave has lower wave length in same frequency,so MCs have more advantages in tiny and integrated electronic device.MCs consist of two or more magnetic materials,corresponding to photonic crystal and phononic crystal,the band structure of spin wave propagateing in MCs could be modulated.The spin wave excitations forbidden from propagating,and this property has achieved industrial application of microware fields.As always,the study of conventional MCs have been reported extensively,the different magnetic materials in MCs have clear boundaries and respective parameters,but that the situation of spatial distribution of parameters has changed continuously is not considered yet.Actually limited by process level and aging of the material,the actual MCs are hard to achieve the standard conventional MCs.This paper presents a new kind of One-dimensional function magnonic crystals.This model is composed by two parts: the matrix part is Ni,whose magnetic parameters are constant,while the central material part's magnetic parameters are the function of space position.The center material model has designed in three function forms.These forms are linear function,quadratic function and cosine function,the dispersion relation of them all calculated by using the plane-wave expansion method.Compared with conventional MCs,it is found that the conventional MCs are only a special form of the function MCs.On this basis,the spin wave's band structure of those one-dimensional MCs has been compared,many obvious differences between function MCs with conventional MCs are exist,and different forms of function MCs also have a lot differences.Those results make the band gap of One-dimensional function MCs be tunable.The study of this work provides a new design method and theoretical support for designing MCs.