Kerr microscopy of small synthetic Ti‐rich titanomagnetite grains
Kerr microscopy of small synthetic Ti‐rich titanomagnetite grains
复制标题
小型合成富钛钛磁铁矿颗粒的克尔显微镜
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
H. Soffel
中科院分区：
文献类型：
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作者：
A. Ambatiello;H. Soffel
利用磁光克尔效应（MOKE）对人工合成的富钛钛磁铁矿（TM）小颗粒（乌尖晶石含量50% ~ 70%）进行了磁畴结构观察。在随机取向晶粒上，可以观察到具有平面畴的简单畴结构或具有弯曲畴和反向尖峰畴的复杂畴结构。除了描述畴图外，还提出了畴内磁化方向的定性确定。磁化强度平行于表面的平面显示出宽畴，畴壁几乎是直的，而磁化强度垂直于表面的平面显示出窄畴和更复杂的图案。利用观察到的随机取向晶粒的畴图和畴内磁化方向的知识，建立了富钛TM的三维畴结构模型。这些富钛钛磁铁矿只有一个容易磁化的方向，显示出真正的单轴特征，尽管磁性矿物是立方的。
Magnetic domain structure observations have been carried out on small synthetic Ti-rich titanomagnetite (TM) grains (ulvospinel content 50%–70%) employing the magneto-optical Kerr effect (MOKE). On randomly oriented grains simple domain structures with planar domains or complex domain structures with curved domains and reverse spike domains have been observed. In addition to the description of the domain pattern, a qualitative determination of the magnetization direction within the domains is presented. Planes with a magnetization parallel to the surface show broad domains with nearly straight domain walls while planes with a magnetization normal to the surface show narrow domains and more complex patterns. With the help of the observed domain patterns on the randomly oriented grains and the knowledge about the magnetization direction within the domains a three-dimensional (3-D) domain structure model for Ti-rich TM is proposed. These Ti-rich titanomagnetites have only one easy direction of the magnetization and show a real unaxial character, although the magnetic mineral is cubic.
By analysing the domain structure of more than a hundred TM particles in a range of size between 1.7 and 20 microns the transition from the single-domain (SD) to the multidomain (MD) state is determined. The fit of the data in this study gives a critical SD size of ≈ 1.1 µm for Ti-rich TM.