Dynamic Behavior Of Magnetic Domains In Magnetic Nanostructures And Spin Wave Driven

Magnetic materials have been major carriers in digital information field from last century. As the requirements of higher storage density and faster reading velocity, domain wall and domain wall motion have been entered into peoples’eyes and attracted a lot of interest. So the dynamics behaviors of magnetic domain in magnetic nanomaterials become the focus of attention.Chapter I presented the magnetic properties of materials and the development of magnetic materials in digital information storage field, the knowledge of the related domain wall and domain wall motion in research results.Chapter II briefly described the basic simulation method mainly used in this paper, such as spin dynamics simulation. Also it gives a presentation of calculating effective field by fast Fourier transform (FFT) and a new approach to find the steady state quickly.Chapter III, we have compared and analyzed the magnetic domain evolution behaviors of ferromagnetic monolayer and ferromagnetic (FM)/antiferromagnetic (AFM) bilayers, and when anti-ferromagnetic coupling is studied in detail, The results indicate that the equivalent width, mass and velocity of magnetic domain wall for FM/AFM bilayers system could be varied with the change of the net magnetization of antiferromagnetic layer, the magnetic anisotropy constants of FM and AFM layer, the exchange coupling constant of antiferromagnetic layer, interface exchange coupling constant and the temperature, and the relevant influences on the coercivity and exchange bias are discussed. The physical mechanisms of the emergence of exchange bias and enhancement of coercivity are discovered by the formation and evolution of the domain wall.The last chapter, we main discussed the transverse domain wall (TW) in ferromagnetic nanostrips drived by spin wave (SW) and studied the domain wall motion under different frequency of SW; we discovered there is a direct relationship between the frequency of SW and the direction of the DW motion. Further discussed the movement of TW for different amplitude of SWs, different coupling pole and different external field types for SW (sine wave, triangle wave, square wave), then we found there is a critical frequency of SW for the TW drived by SWs.