Micromagnetic simulations on demagnetization processes in anisotropic Nd2Fe14B magnets
来源期刊：Journal of Rare Earths2019年第6期
论文作者：Lei Li Shengzhi Dong Rui Han Kuikui Song Dong Li Minggang Zhu Wei Li Wei Sun
文章页码：628 - 632
摘 要：Individual grains with diverse dimensional parameters were introduced to investigate the magnetization reversals in anisotropic Nd2 Fe14B magnets. The micromagnetic simulations were carried out via Object Oriented MicroMagnetic Framework（OOMMF）. With the same bottom area and height, analysis results show that the coercive fields for different bottom shapes are of similar values. Designed as a cubic grain,the coercive field presents descending tendency as grain volume ascends. Under constant grain volume,with aspect ratio increasing, the coercive field decreases in the beginning and increases soon. Based on the demagnetization field vector, the effects of bottom shape, grain volume and aspect ratio on the coercive field can be explained. The nucleation point is chosen to discuss. Its synthetic field and reversal field are calculated by parallelogram law and inverse external field equation, respectively. The synthetic field equal to the reversal field is defined as critical field, which always shows the same tendency as the coercive field for all cases of this study. It can be concluded that critical field is qualified to be a reference index to measure the magnitude of coercive field.
Lei Li1，Shengzhi Dong1，Rui Han1，Kuikui Song1，Dong Li1，Minggang Zhu1,2，Wei Li1,2，Wei Sun2
1. Division of Functional Materials Research,Central Iron and Steel Research Institute2. National Engineering Research Center for Magnetic Materials
摘 要：Individual grains with diverse dimensional parameters were introduced to investigate the magnetization reversals in anisotropic Nd2 Fe14B magnets. The micromagnetic simulations were carried out via Object Oriented MicroMagnetic Framework（OOMMF）. With the same bottom area and height, analysis results show that the coercive fields for different bottom shapes are of similar values. Designed as a cubic grain,the coercive field presents descending tendency as grain volume ascends. Under constant grain volume,with aspect ratio increasing, the coercive field decreases in the beginning and increases soon. Based on the demagnetization field vector, the effects of bottom shape, grain volume and aspect ratio on the coercive field can be explained. The nucleation point is chosen to discuss. Its synthetic field and reversal field are calculated by parallelogram law and inverse external field equation, respectively. The synthetic field equal to the reversal field is defined as critical field, which always shows the same tendency as the coercive field for all cases of this study. It can be concluded that critical field is qualified to be a reference index to measure the magnitude of coercive field.
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