Fabrication of periodic arrangement of ferromagnetic nanoparticles as a potential application to future high density magnetic strage media

在这项研究中，我们研究了利用原子法、阶梯法和光刻技术在聚苯乙烯微球中制备周期性排列的铁磁性纳米颗粒，以期在未来的高密度磁存储介质中得到潜在的应用。结果，通过电子束沉积在偏角的NaC l(001)衬底上，成功地制备出了周期性排列的4 nm尺寸的FeS纳米粒子。在673K沉积后，制得的纳米脚为单晶，具有四方L10有序结构，比以往报道的制备温度降低了100K以上。磁性矫直力随纳米脚颗粒尺寸的减小而减小，这可以用非常小的脚纳米颗粒的磁矩的热波动来解释。然后，我们用精细原子台阶法制备了Si(113)和SrTiO_3(001)单晶衬底。在这些台阶衬底上沉积Au、Ag、Pd、Pt等贵金属元素，形成了密度较高的金属纳米颗粒，但尽管每个衬底表面都存在周期性的原子台阶，但却没有实现纳米颗粒沿台阶边缘的周期性排列。光刻技术-利用聚苯乙烯球体的周期性排列，在氧化镁衬底上形成金和钯纳米点周期阵列。我们的下一步是控制聚苯乙烯小球在衬底上的分布。

In this study, we have examined a fabrication of periodically arranged ferromagnetic nanoprticles by using atomic, steps and lithography with polystyrene spheres for potential applications to future high density magnetic storage media. As a result, periodic arrangement of 4-nm-sized Feet nanoparticles was successfully produced by electron beam deposition onto an off-angle NaCl (001) substrate. Fabricated Feet nanoparticles were single crystalline with tetragonal L1o ordered structure just after the deposition at 673K.This fabrication temperature is more than 100K lower than that of previous reports. Magnetic coercivity decreased with decreasing the particle size of Feet, which can be explained by the thermal fluctuation of magnetic moments of very small Feet nanoparticles. Then we prepared Si(113) and SrTiO3(001) single crystal substrates with fine atomic steps. Deposition of noble metal elements like Au, Ag, Pd, Pt onto these step substrates resulted in formation of fine metal nanoparticles with high density, but periodic arrangement of nanoparticles along the step edges were not achieved in spite of the existence of periodic atomic steps on each substrate surfaces. Lithography technique ~ using periodic arrangement of polystyrene spheres lead to formation of Au and Pd nano-dot periodic arrays on MgO substrates. Our next step is to control the distribution of polystyrene spheres on the substrate