Development of High Frequency Magnetic Cores with Low Loss in Forms of Thin Foil and Wire by Means of Domain Wall Pinning

近年来，为了实现电子仪器的进一步小型化，对电源小型化的要求越来越强烈。人们已经认识到，提高工作频率可以响应小型化的需求。因此，研制适用于高频磁场的磁性材料是实现电子仪器小型化的关键。在本研究中，人们致力于发展一种非晶态磁性材料，其形式为薄箔和细丝，其磁化过程通过在高频场中的磁化旋转来进行。由于非晶态材料中不存在磁晶各向异性，引入感生各向异性可以显著控制其磁性能。根据非晶态材料的这一特性，我们试图将磁化壁钉扎在薄箔和金属线上，以实现高频磁场中的磁化旋转。首先，自旋…通过磁场壁观察和计算机模拟，进一步明确了非晶态材料钉扎壁的结构，并将研究结果应用于高频材料的研制。所研制的非晶箔和非晶丝的磁性总结如下。(1)在频率为100 KHz1 MHz的磁场中，厚度为4.7微米的壁钉扎薄箔在磁化到0.1T时的铁损分别为13 mW/cc和860 mW/cc。这些数值只有传统高频材料损耗的30%-40%。在1 MHz频率下，壁钉扎箔还表现出1500的高初始磁导率。所开发的材料可应用于频率高达1 MHz的DC-DC转换器的铁心。壁钉扎非晶丝在纵向和周向磁化时也表现出高电感。在100 kHz和1 MHz频率下，L宠物的单位长度(Cm)分别为3h和1.5h。由于短片导线通过导线的直流电很容易在圆周方向上磁化。从而使壁销线可以作为电子线路中的小电感元件使用。较少

Recently, miniaturization of power supply is demanded strongly to achieve further down-sizing of the electronic instruments. It has been well recognized that the increase of operation frequency can respond th e demand of miniaturization. So that, a key to achieve the miniaturization of electronic instrument is in the development of magnetic materials usable in a high frequency magnetic field. In the present investigation, and effort was made to develop a amorphous magnetic material in forms of a thin foil and wire whose magnetization process proceeds by magnetization rotation in a high frequency field. Because of the absence in magnetocrystalline anisotropy in amorphous materials, their magnetic properties can be controlled markedly by introducing the induced anisotropy. Depending on this characteristic property in amorphous materials, we tried to pin the domain walls in the thin foil and wire to attain the magnetization rotation in a magnetic field with high frequency.First, the spin … More structure in the pinned wall of amorphous materials was made clear by domain wall observation and computer simulation, and then the results were applied to develop the high frequency materials . Magnetic properties of the developed amorphous foil and wire are summarized as below. (1)The wall pinned thin foil with 4.7 mum thickness exhibits very low iron loss of 13mW/cc and 860mW/cc when magnetized up to 0.1T in magnetizing fields with frequency of 100KHz 1MHz, respectively. Those values are as small as 30-40% of the loss of conventional high frequency materials. The wall pinned foil exhibits also the high initial permeability of 1,500 at 1MHz. The developed materials could be applied to a core in DC-DC converter operable at frequency as high as 1MHz. The wall pinned amorphous wire also exhibits high inductance when magnetized in both longitudinal and circumferential directions. The values of L pet unit length(cm) are 3 and 1.5H at frequency of 100kHz and 1MHz, respectively. As the short piece wire can be magnetized easily in the circumferential direction by direct current through the wire. So that the wall pinned wire could be usable as a small inductance element in electronic circuits. Less