Synthesis of Granular Layers by Ion Implantation and the GMR Properties

离子注入颗粒层的合成及其 GMR 特性

基本信息

批准号：
13650355
负责人：
HAYASHI Nobuyuki
金额：
$ 2.37万
依托单位：
Kurume Institute of Technology (2002)Hosei University (2001)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Main results are summarized as follows:1) Dose dependence of GMR effect and magnetoresistance (MR) ratio ;In the Fe/Al_2O_3 granules synthesized by ion implantation the highest MR ratio is obtained as 7.5% at the dose of 1.5×10^<17> ions/cm^2, where the α iron clusters are observed to be in critical sizes to do a transition from superparamagnetic to ferromagnetic states. Thus, superparamagnetic nanoclusters dispersed in the insulating oxide.2) Estimation of the size distribution in nano-sized Fe clusters ;The size distribution was estimated from the analysis of conversion electron Mossbauer spectra and the magnetization measurements. At the dose of 1.5×10^<17> ions/cm^2 the radii of Fe are estimated to be in wide distribution with the two peak values of 2.1 nm and 4 nm.3) Evolution of new TMR granules and treatment to improve TMR characteristics ;Fe ions are implanted into single crystals of MgO and amorphous SiO_2 to investigate the possibility of synthesizing various GMR granules. However, it is found that the MR ratios for the both nanocomposites are about 1 % at most, in contrast to Fe/Al_2O_3. However, we have found that in the implanted layers the dispersion state is altered after annealing in N_2 atmosphere at such low temperature as 550 K, which leads to the improvement of GMR properties, e.g., the increase of MR ratio to 3.5 % in Fe/MgO.5) Development of new type of alloy nanoclusters ;We have succeeded in presenting an evidence that the clusters of Fe-Co alloys can be synthesized by sequential implantation of Fe and Co ions. It is expected that the syntheses of alloy clusters by the implantation develop new fields of material science and magnetism.

主要结果概括如下：1)GMR效应和磁阻(MR)比值的剂量依赖性;在离子造粒法合成的Fe/Al_2O_3中，在1.5×10^<17>剂量下获得最高MR比值，为7.5%。 ions/cm^2，其中观察到 α 铁簇处于临界尺寸，可以从超顺磁态转变为铁磁态。因此，超顺磁纳米团簇分散在绝缘氧化物中。2）纳米Fe团簇尺寸分布的估计；通过转换电子穆斯堡尔谱分析和1.5×10^剂量下的磁化测量来估计尺寸分布。 <17> ions/cm^2 Fe的半径估计分布广泛，有2.1 nm和4 nm两个峰值。3）新的演化TMR颗粒及其改善TMR特性的处理；将Fe离子注入到MgO和非晶SiO_2单晶中，研究合成各种GMR颗粒的可能性，但发现两种纳米复合材料的MR比率最多约为1%。，与Fe/Al_2O_3相反，我们发现在N_2气氛中退火后，注入层中的色散状态发生了改变。 550 K 的低温，这导致 GMR 性能的改善，例如，Fe/MgO 中的 MR 比增加到 3.5%。5) 新型合金纳米团簇的开发;我们已经成功地提出了证据表明该团簇Fe-Co合金可以通过Fe和Co离子的顺序注入来合成，预计通过注入合成合金团簇将开拓材料科学和磁性的新领域。