Printing Nearly-Discrete Magnetic Patterns Using Chemical Disorder Induced Ferromagnetism
Printing Nearly-Discrete Magnetic Patterns Using Chemical Disorder Induced Ferromagnetism
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DOI：
10.1021/nl404521c
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发表时间：
2014-02-01
期刊：
影响因子：
10.8
通讯作者：
Fassbender, Juergen
中科院分区：
文献类型：
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作者：
Bali, Rantej;Wintz, Sebastian;Fassbender, Juergen
在某些由磁性和非磁性物质组成的合金中，铁磁性可以通过化学无序的存在而被激活。这种现象与最近邻磁性原子数量的增加以及由于无序位置的存在而导致的电子能带结构的局部变化有关。诱导无序的一种方法是通过将化学有序的合金暴露于高能离子;由离子形成的碰撞级联将原子从它们的有序位置敲出，并且伴随的空位在室温下通过原子的热扩散随机填充。有序结构由此经历转变成亚稳固溶体。在这里，我们展示了图案化的高度分辨的磁性结构，利用的Fe 60 Al 40合金的饱和磁化强度的大幅增加，由微妙的原子位移触发。的S形特性和敏感的原子位移上的诱导磁化强度的依赖性表现出一个子50 nm的图案化分辨率。执行由类似于40 nm宽的间隔物分隔的条带形式的磁性区域的图案化，其中磁体/间隔物/磁体结构在零场中展现出可重新编程的平行（向上箭头/间隔物/向上箭头）和反平行（向上箭头/间隔物/向下箭头）磁化配置。可以通过离子诱导相变调节磁行为的材料可以允许使用现有的横向图案化工具制造新型自旋传输和存储器件。
Ferromagnetism in certain alloys consisting of magnetic and nonmagnetic species can be activated by the presence of chemical disorder. This phenomenon is linked to an increase in the number of nearest-neighbor magnetic atoms and local variations in the electronic band structure due to the existence of disorder sites. An approach to induce disorder is through exposure of the chemically ordered alloy to energetic ions; collision cascades formed by the ions knock atoms from their ordered sites and the concomitant vacancies are filled randomly via thermal diffusion of atoms at room temperature. The ordered structure thereby undergoes a transition into a metastable solid solution. Here we demonstrate the patterning of highly resolved magnetic structures by taking advantage of the large increase in the saturation magnetization of Fe60Al40 alloy triggered by subtle atomic displacements. The sigmoidal characteristic and sensitive dependence of the induced magnetization on the atomic displacements manifests a sub-50 nm patterning resolution. Patterning of magnetic regions in the form of stripes separated by, similar to 40 nm wide spacers was performed, wherein the magnet/spacer/magnet structure exhibits reprogrammable parallel (up arrow/spacer/up arrow) and antiparallel (up arrow/spacer/down arrow) magnetization configurations in zero field. Materials in which the magnetic behavior can be tuned via ion-induced phase transitions may allow the fabrication of novel spin-transport and memory devices using existing lateral patterning tools.