In situ observations of domain wall motion in Mn Zn and Ni Zn ferrites by Lorentz microscopy and electron holography
In situ observations of domain wall motion in Mn Zn and Ni Zn ferrites by Lorentz microscopy and electron holography
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DOI：
10.1016/j.jmmm.2005.12.007
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发表时间：
2006-10
影响因子：
2.7
通讯作者：
Takehiro Kasahara;H. Park;D. Shindo;H. Yoshikawa;T. Sato;Kondo Koichi
中科院分区：
文献类型：
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作者：
Takehiro Kasahara;H. Park;D. Shindo;H. Yoshikawa;T. Sato;Kondo Koichi
用Lorentz显微镜和电子全息术对外加磁场的锰锌铁氧体和镍锌铁氧体中的磁畴壁运动进行了原位观察。结果表明，两种铁氧体的平均晶粒度均为10μm左右，孔洞大小在0.2~1.1μm之间，洛伦兹显微镜和外加磁场的原位观察表明，在锰锌铁氧体中，磁化壁易跨越晶界移动，而在镍锌铁氧体中，磁化壁沿晶界移动，但被钉扎在晶界和孔洞上。用电子全息术对Ni-Zn铁氧体的原位观察表明，晶界的磁化壁钉扎延缓了平行于外加磁场方向的磁通的敏感增加，这被认为是导致高磁滞损耗的原因。
Domain wall motion in Mn–Zn and Ni–Zn ferrites with applied magnetic fields is investigated by in situ observations with Lorentz microscopy and electron holography. It is found that both Mn–Zn and Ni–Zn ferrites have a mean grain size of approximately 10μm and several pores with sizes ranging from 0.2 to 1.1μm. In situ observations by Lorentz microscopy with an applied magnetic field reveals that in Mn–Zn ferrite, the domain walls move easily across the grain boundary, while in Ni–Zn ferrite, the domain walls move along the grain boundary but are pinned at the grain boundary and pores. From in situ observations of Ni–Zn ferrite by electron holography, it is clarified that domain wall pinning at the grain boundary retards a sensitive increase in magnetic flux parallel to the applied field direction, which is considered to result in high hysteresis loss.