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Physical property of two components nono-crystals prepared with GDM

GDM制备的二组分非晶的物理性质

基本信息

批准号：
10650647
负责人：
KITA Eiji
金额：
$ 1.98万
依托单位：
University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

项目摘要

In this research project, nano-crystals composed of multi-elements were investigated. 2 different techniques, which are modified from Gas condensation and Deposition Method (GDM), were tested to realize 2 components nano-crystals. Additionally, basic properties of single element nanocrystals produced by the simple GDM are also reported.As basics of the multi-element nano-crystal system, magnetism of GDM Ni nano-crystals was investigated. As deposited films were composed of fine particles with approximately 9 nm in diameter. Thermal annealing up to 400°C increased the grain size of around 20 nm. Coercive forces of the nano-crystals vary in accordance with the - 6 powers of grain size smaller than 13nm. This is explained by the Random Anisotropy Model. Effective local magnetic anisotropy is deduced to be 1.9-3.5 x 104 J/ m3 and this magnitude is 2-5 times larger than that of bulk Ni. From the field cool magnetization measurement, Hc shift due to exchange anisotropy was not observed. The … More antiferromagnetic layer around grains originated from oxidation seems not to be responsible for the anisotropy.Two components nano-crystals including ferromagnetic metals such as Fe and Co were fabricated by mixing ultrafine particle flows from two individual sources. In the case where fine particles were mixed on a substrate, the composition was modulated in a large scale and this means flows do not mix well in this way. Next, we mixed the flows in the transfer tube and the modulation was improved, however, clear separation of the elements was found in an each trace of a mixed beam. Another technique modifying GDM, where fine particles were mixed with other sputtered metals on the substrate, has been tested to realize granular materials. By this way the mixing was remarkably improved compared with former ways. GMR was expected in a case of Co-Ag system, however only small magneto-resistance was found. This may be attributed to the size of Co particles and further investigation is planned. Less

在这个研究项目中，研究了由多元素组成的纳米晶体。测试了从气体冷凝和沉积法（GDM）改进而来的两种不同技术，以实现两种组分的纳米晶体。此外，还报道了简单GDM制备的单元素纳米晶体的基本性质。作为多元素纳米晶体体系的基础，研究了GDM Ni纳米晶体的磁性。沉积的薄膜由直径约为 9 nm 的细颗粒组成。高达 400°C 的热退火使晶粒尺寸增加了约 20 nm。纳米晶体的矫顽力根据小于13nm的晶粒尺寸的-6次方变化。这是通过随机各向异性模型来解释的。推导出有效局部磁各向异性为1.9-3.5 x 104 J/ m3，这个数量级比块体Ni大2-5倍。根据场冷磁化强度测量，没有观察到由于交换各向异性导致的 Hc 偏移。源自氧化的颗粒周围的反铁磁层似乎与各向异性无关。通过混合来自两个单独来源的超细颗粒流，制造了包括铁磁金属（如铁和钴）的两种纳米晶体成分。在细颗粒在基材上混合的情况下，成分被大规模调节，这意味着流动不能以这种方式很好地混合。接下来，我们在传输管中混合流动，并且调制得到了改进，但是，在混合光束的每条迹线中都发现了元素的明显分离。另一种改进 GDM 的技术已被测试以实现粒状材料，其中细颗粒与基底上的其他溅射金属混合。通过这种方式，与以前的方式相比，混合效果得到了显着改善。 GMR 预计出现在 Co-Ag 系统的情况下，但只发现了很小的磁阻。这可能归因于钴颗粒的尺寸，并计划进一步研究。较少的