Development of nano-meter multilayered magnetic film with super low energy loss and application for electric motor

采用对靶式射频磁控溅射系统制备了多层磁环型磁芯，并测量了其磁能损耗。在恒定磁场条件下，由于磁畴壁的共振，能量损耗-驱动频率曲线在约200 kHz处出现峰值。结果表明，随着磁场幅值的增大，共振频率向高值方向移动，出现峰值坍塌现象。这一现象与H.Okuno提出的混沌理论对磁能损失的预测是一致的。结果表明，磁畴壁的运动非常复杂，具有连续的功率谱。用递归图的方法找到了重构吸引子的分形结构，证明了非规则的磁区-壁运动是确定性系统中的混沌，而不是随机系统中的噪声等随机性。综合评价采用关联维分析、混沌区域图、混沌控制方法和磁能损失等方法。在关联维非整数为8.83的情况下，非规则的磁区壁面运动必然是混沌运动。结果表明，除驱动场的大幅-高频或小幅-低频外，其余区域均存在混沌运动，混沌区域底部附近的边界由磁区-壁共振区形成。提出了一种半周期延时反馈控制方法来控制混沌域壁运动，该方法具有最好的可控性和最小的磁能损失。上述研究成果已在国际会议上发表。对提出的磁能损失混沌理论和降低磁能损失的控制方法进行了评价。

The multilayered magnetic ring-type core was made by a facing-target-type RF magnetron sputtering system and the magnetic energy loss was measured. The energy loss vs. drive frequency curve showed the peak at about 200 kHz in the condition of constant magnetic field because of the resonance of magnetic domain-wall. It was found that the resonance frequency shifted toward higher values with increasing the amplitude of magnetic drive field and the peak collapse happened. This phenomenon was coincident with the prediction of chaos theory for magnetic energy loss proposed by H.Okuno. It was found that the magnetic domain-wall showed very complicated motion with a continuous power spectrum. The fractal structure in the reconstructed attractor was found by the method of recurrence plot and the irregular domain-wall motion was certified to be the chaos in the deterministic system and not the randomness such as the noise in the stochastic system. The general evaluation was performed by using the correlation-dimension analysis, the map of chaos region, the method of controlling chaos and the magnetic energy loss. With the non-integral number of 8.83 for correlation-dimension, the irregular domain-wall motion was certainly proved to be the chaos. The chaotic domain-wall motion was found to exist in the region except large amplitude-high frequency or small amplitude-low frequency of drive field and the border near the bottom of chaos region was found to be made by the region of domain-wall resonance. The half period extended delayed feedback control method was developed to control the chaotic domain-wall motion, which showed the best controllability and the least magnetic energy loss. The above results were presented in the international conference. The proposed chaos theory of magnetic energy loss and the control method of decreasing it underwent an evaluation.