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

近来，强烈要求电源的小型化以实现电子仪器的进一步小型化。工作频率的提高可以满足小型化的要求。因此，研制能在高频磁场中工作的磁性材料是实现电子仪器小型化的关键。在本研究中，致力于开发薄箔和线形式的非晶磁性材料，其磁化过程通过在高频场中的磁化旋转进行。由于非晶材料中不存在磁晶各向异性，因此通过引入感生各向异性可以显著地控制其磁性能。根据非晶材料的这种特性，我们试图钉扎薄箔和线中的畴壁，以在高频磁场中实现磁化旋转。 ...更多信息 通过畴壁观察和计算机模拟，明确了非晶材料钉扎畴壁的结构，并将其应用于高频材料的研制。所开发的非晶箔和线的磁特性总结如下。（1）厚度为4.7 μ m的钉扎薄箔在频率为100 KHz ~ 1 MHz的磁场中磁化至0.1T时，铁损分别为13 mW/cc和860 mW/cc。这些值小到传统高频材料损耗的30-40%。壁钉扎箔还表现出在1 MHz下1，500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转换器的核心。当在纵向和周向磁化时，壁钉扎非晶丝也表现出高电感。在100 kHz和1 MHz频率下，L PET单位长度（cm）的值分别为3和1.5H。由于短的金属丝可以很容易地被通过金属丝的直流电在圆周方向上磁化。因此，壁钉扎线可用作电子电路中的小电感元件。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