Magnetic properties of Co/Pt multilayers deposited on silicon dot arrays
Magnetic properties of Co/Pt multilayers deposited on silicon dot arrays
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DOI：
10.1103/physrevb.62.12271
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发表时间：
2000-11
影响因子：
3.7
通讯作者：
S. Landis;B. Rodmacq;B. Dieny
中科院分区：
文献类型：
--
作者：
S. Landis;B. Rodmacq;B. Dieny
通过标准的光刻和蚀刻技术制备了尺寸小于200nm的硅点阵列，然后覆盖不同的（Co 0.5 nm/Pt 1.8 nm）多层膜，这些多层膜表现出垂直的磁各向异性。在无图案衬底上，矫顽力场在120和400 Oe之间变化，这取决于缓冲层的厚度和层数。磁力显微镜（MFM）图像显示约1.2 μ m大小的磁畴。在有图案的硅衬底上沉积这些多层材料表明，即使磁性材料的量占点高度的60%，磁点的轮廓也与初始硅点的轮廓相同。原子力显微镜的横截面显示，可忽略不计的材料沉积在点的侧壁上。具有足够大的点间距以探测凹槽底部的阵列的MFM图像显示，点之间区域的磁畴与未图案区域的磁畴大小相同，尽管它们的矫顽力从170增加到300 Oe。在点的顶部，观察到单畴结构，点的矫顽力场范围为1600 ~ 2400 Oe。这种开关场的分布仅弱依赖于点的大小，主要与点的详细形状（特别是角的锐度）有关，而与它们的静磁相互作用无关。这赋予每个单独的点一个定义良好的强制场。给定点的磁化反转对其第一个邻居的影响很弱，这意味着在本研究中使用的Co和Pt厚度范围内，这些点基本上是相互独立的。以同样的方式，凹槽底部的连续磁性层没有介导显著的耦合。这些结果被我们所研究的各种几何形状的磁点-点和点-槽相互作用的微磁计算所证实。
Arrays of silicon dots down to 200 nm in size have been prepared by standard lithography and etching techniques, and then covered by different (Co 0.5 nm/Pt 1.8 nm) multilayers which exhibit perpendicular magnetic anisotropy. On unpatterned substrates, the coercive field varies between 120 and 400 Oe, depending on the buffer thickness and on the number of layers. Magnetic force microscopy (MFM) images show magnetic domains about 1.2 μ m in size. Deposition of these multilayers on patterned silicon substrates shows that the profile of the magnetic dots is the same as the initial Si dot profile even when the amount of magnetic material represents 60% of the dot height. Atomic force microscopy cross sections indicate that a negligible amount of material is deposited on the side walls of the dots. MFM images of arrays with a dot spacing large enough to explore the bottom of the grooves show that the magnetic domains in areas between the dots are of the same size as on the unpatterned area, although their coercive field is increased from 170 to 300 Oe. On the top of the dots, single-domain configurations are observed, and the coercive field of the dots ranges from 1600 to 2400 Oe. This distribution of switching fields, which only weakly depends on the dot size, is mainly related to the detailed shape of the dots (in particular the sharpness of the corners) and not to their magnetostatic interaction. This confers to each individual dot a well-defined coercive field. The magnetization reversal of a given dot weakly influences its first neighbors, which means that the dots are essentially independent of each other for the range of Co and Pt thickness used in this study. In the same way, no significant coupling is mediated by the continuous magnetic layer in the bottom of the grooves. These results are confirmed by micromagnetic calculations of the magnetic dot-dot and dot-groove interactions for the various geometries that we have investigated.