The Magnetization Dynamics In Magnetic Nanotubes

Owing the tubular structure the nanotubes has the unique properties compared with other nanomaterials.Therefore,the study of nanotubes is very important..For magnetic nanotubes,magnetism is one of the main features.This can be used to record information and realize information transmission.In this paper,we mainly investigate the domain wall dynamics in ferromagnetic nanotubes driven by a magnetic field.The thesis is divided into the following content:In the first chapter,we mainly introduced the discovery and properties of ferromagnetic nanotubes,and the analytical form of the energy for the ferromagnetic nanotubes.This energy includes the exchange energy,zeeman energy,the anisotropic energy and demagnetizing energy,respectively.In the second chapter,the dynamic motion of magnetization is discussed in detail,and the two driving force for the domain wall movement is analyzed,respectively.In the third chapter,in terms of numerical technique we solve the Landau-lifshita-Gilbert equation and study the domain wall motion in ferromagnetic nanotubes driven by a external field.The effect of nanotubes thickness on the domain wall width and velocity is analyzed in detail.We find that there exists a difference with general nanowire and nano film.When the thickness of the nanotubes is zero,we design a kind of spatial and temporal magnetic field to control the domain wall movement velocity.