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

为了实现电子仪器的进一步小型化，对电源小型化提出了强烈的要求。提高工作频率可以满足小型化的要求，这一点已经得到了广泛的认识。因此，开发可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，我们努力研制了一种非晶磁性材料，它的磁化过程是通过在高频场中的磁化旋转来进行的。由于非晶材料中磁晶各向异性的缺失，引入诱导各向异性可以明显地控制非晶材料的磁性能。根据非晶材料的这一特性，我们尝试将畴壁钉在薄箔和金属丝上，以实现高频磁场中的磁化旋转。首先，通过畴壁观察和计算机模拟，明确了非晶材料钉住壁上的自旋结构，并将结果应用于高频材料的开发。所研制的非晶箔和金属丝的磁性能总结如下。(1)在频率为100KHz 1MHz的磁场中，当磁化强度达到0.1T时，厚度为4.7 μ m的壁钉薄箔的铁损较低，分别为13mW/cc和860mW/cc。这些值仅为传统高频材料损耗的30-40%。壁钉箔在1MHz时也表现出1500的高初始磁导率。所研制的材料可用于工作频率高达1MHz的DC-DC变换器的磁芯。当纵向和周向磁化时，壁钉非晶线也表现出较高的电感。在100kHz和1MHz频率下，L pet单位长度（cm）值分别为3和1.5H。由于短片导线很容易被通过导线的直流电沿周向磁化。因此，壁钉线可以作为小型电感元件在电子电路中使用。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