Study On Microwave Magnetic Properties Of Plate-like Magnetic Particles

Since the 1970 s,magnetic nanomaterials have experienced a process from generation to development to growth,and gradually become a new magnetic material.The special effects of magnetic nanoparticles,including quantum size effect,small size effect,surface effect and macroscopic quantum tunneling effect,will change the magnetic performance strongly and show unique magnetic properties,which has attracted much attention.Magnetic properties of magnetic particles can be adjusted by the composition,preparation process,heat treatment and so on.In this paper,we focus on the influence of the magnetic interaction on the static and dynamic magnetic properties of magnetic particles influenced by the defects and particles.The main work can be summarized as follows:The effects of hole shape and pit-shape defect on the static magnetic moment distribution and magnetic spectrum of rectangular ferromagnetic nanosheets were investigated by micro-magnetic simulation.The results show that it depends on the change of defect position and the change of size and shape of defects.The defects may cause the main resonance of the magnetic spectrum to move to a lower frequency position.These results provide a reference for the control and design of the static and dynamic properties of rectangular ferromagnetic nanosheets by patterning.The effects of relative position,particle spacing and magnetic anisotropy on the magnetic properties of two rectangular ferromagnetic nanosheets were also investigated by micro-magnetic simulation.The results show that the relative position and distance between particles can influence the distribution of two rectangular ferromagnetic nano film resonant frequency.When the two rectangular nano magnetic anisotropy direction angle was increased from 0 ° to 30 °,the magnetic properties did not change obviously.But when it was increased from 30 ° to 90 °,its magnetic properties are sensitive to the direction of magnetic anisotropy.In addition,the results show that the magnetic anisotropy of two rectangular ferromagnetic nanosheets can significantly affect the number,intensity,peak width and frequency distribution of resonance peaks.Therefore,we can change the magnetic properties of the ferromagnetic nanosheets by changing the relative position,particle spacing and magnetic anisotropy of the nanosheets,which can be used to prepare microwave absorbing materials with various frequencies and wide absorption bands.