Micromagnetic Simulation Of FMR And FMR Characteristics Of ?-Fe_2³N Magnetic Thin Film

Ferromagnetic resonance?FMR?describes the resonant magnetic response of a magnetic material due to the excitation of electromagnetic radiation.It is mainly used to study the magnetic properties of magnetic substances,such as magnetic anisotropy,etc.,which is of great significance to the development of spintronics and other fields.This thesis focus on the study of ferromagnetic resonance phenomenon,including the FMR micromagnetic simulation and FMR characteristics of?-Fe_2³N magnetic thin film,and has achieved the following results:The micromagnetic simulation software OOMMF was adopted to simulate the FMR characteristics of the ferromagnetic thin film.By studying the factors that affect the FMR characteristics,we found that the magnitude of the external magnetic field has an influence on the resonance frequency,and the damping factor determines how fast the system reaches equilibrium.On this basis,we studied the FMR characteristics of single-layer and multi-layer nanosheets,including the FMR characteristics of rectangular and other single-layer nanosheets.By changing the width of the rectangular nanosheets,the competition of the exchange and the demagnetization energies results in splay pattern at the ends of nanosheets.This splay pattern causes a weak resonance mode to appear and weakens as the width increases.Further more,we simulated three-layer thin-film structure,and three FMR resonance modes were found,whose resonant frequencies all decrease with the increase of interlayer thickness,while not in the same pace.Multiple sets of?-Fe_2³N magnetic thin films with different Fe/N ratios and Cu-doped?-Fe_2³N magnetic thin films were prepared by means of magnetron sputtering technique,and FMR characteristics were studied.By controlling the N₂ flow rate,?-Fe_2³N magnetic thin films with different Fe/N ratios were prepared on Ga N and Al₂O₃ substance.We found that when the N₂ flow rate is small,Fe:N is close to 3,in which case the samples shows ferromagnetic characteristics.Besides,as??the angle between the external magnetic field and the surface of the film?increases,larger external magnetic field is observed when reaching ferromagnetic resonance state.However,when the N₂ flow rate is high and Fe:N is close to 2,in which case the samples exhibits paramagnetic characteristics.As a result,no ferromagnetic resonance phenomenon can be observed.When we prepared?-Fe_2³N magnetic thin films under lower temperature,more than one resonance mode is observed,among which we found a unique resonance peak that doesn't change with?.We believe that this resonant mode may result from?-Fe particles in the sample.Besides,Cu-doped?-Fe_2³N samples are also prepared,we found that the ferromagnetic resonance spectrum is similar to the undoped ones when the doping concentration is low.However,when the doping concentration is high,multiple resonance modes can be observed,which also changes with?.These results provide an experimental basis for further study of the magnetic properties of?-Fe_2³N thin films?such as magnetic anisotropy?and the application of?-Fe_2³N thin films in the field of magnetoelectronic device design.