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Composite magnetic films for optically assisted magnetic recording (rapid thermally annealed FePt crystalline grains/magneto optical recording film)

光辅助磁记录用复合磁性薄膜（快速热退火FePt晶粒/磁光记录薄膜）

基本信息

批准号：
18560347
负责人：
ITOH Akiyoshi
金额：
$ 2.37万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

项目摘要

In this study, we discussed the composite magnetic recording media, consisting of FePt grain under layer with TbFeCo continuous layer, as high density optically assisted recording media over 1 Tbit/in^2. Due to its high magnetic anisotropy K_u and the capability of forming small grains, FePt is a leading candidate for high density magnetic recording media that are preferable to overcome the thermal fluctuation of small magnetic grains. FePtX (X=Cu, Ni) prepared by Rapid Thermal Annealing (RTA). To increase areal packing density of FePtX grains, a SiO_2 Substrate having self-organized nano-pores was used as a nano-template. Main results were followings1) Fabrication of nano-dent array substrate by self-assemble methodWe succeeded to fabricate SiO_2 film having highly ordered nano-pores inside, and found that the dilution of a solvent with ethanol is effective to thinning the film thickness preparing by spin coring method.2) Decrease of the Curie temperature of FePt by Cu or Ni dopingSubstituting Cu or Ni for some of the Fe is expected to reduce the K_u i. e. Curie temperature T_c (FePt, T_c=500℃ at room temperature). We fabricated well isolated FePtX(X=Cu, Ni) particles by RTA, and confirmed the doping effect to reducing Curie temperature. Deferent content dependence was found in each element.3) Micro-magnetic simulations of domain shape incomposite magnetic recording mediaSimulated result of composite magnetic film consisting of FePt grains under layer and TbFeCo continuous layer shows tiny domain could be formed (domain diameter 22 nm at the TbFeCo surface). Even the spacing between each grain decreased less than the theoretical domain wall width, FePt particles act as domain pinning sites of TbFeCo layer.

在这项研究中，我们讨论了复合磁记录介质，由FePt颗粒底层与TbFeCo连续层组成，作为超过1 Tbit/in^2的高密度光辅助记录介质。由于其高的磁各向异性K_u和形成小晶粒的能力，FePt是高密度磁记录介质的主要候选者，其优选地克服小磁性晶粒的热波动。采用快速热退火（RTA）方法制备了FePtX（X=Cu，Ni）.为了提高FePtX颗粒的面堆积密度，采用具有自组织纳米孔的SiO_2衬底作为纳米模板。主要研究结果如下：1）自组装法制备纳米凹坑阵列基底我们成功地制备了内部具有高度有序纳米孔的SiO_2薄膜，并发现用乙醇稀释溶剂对用旋转成核法制备的薄膜厚度变薄是有效的。2）Cu或Ni掺杂降低FePt的居里温度用Cu或Ni取代部分Fe，可望降低K_u_i。e.居里温度T_c（FePt，室温T_c=500℃）。通过快速热分析制备了具有良好隔离性的FePtX（X=Cu，Ni）颗粒，证实了掺杂对降低居里温度的影响。3）复合磁记录介质中磁畴形状的微磁学模拟对由FePt颗粒底层和TbFeCo连续层组成的复合磁性薄膜的模拟结果表明，在TbFeCo表面可以形成微小的磁畴（磁畴直径为22 nm）。即使晶粒间的间距减小到小于理论畴壁宽度，FePt颗粒仍充当TbFeCo层的畴钉扎位点。