Preparation of granular-tunneling magnetoresistive materials by a multi-step ion implantation method

多步离子注入法制备粒状隧道磁阻材料

• 批准号: 15560631
• 负责人: WAKABAYASHI Hidehiko
• 金额: $ 1.92万
• 依托单位: Musashi Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560631/
• 关键词: ion implantation; tunneling magnetoresistance; granular; metallic iron-ultrafine particle; superparamagnetism; Mossbauer spectroscopy; particle size control; annealing; トンネル型磁気抵抗; 超微粒子; 金属鉄微粒子; 粒径分布; 選択的成長

For granular tunneling magnetoresistive materials, it is desirable that medium-sized superpararnagnetic fine particles are dispersed in an insulator matrix as densely as possible. The present study was done to demonstrate that selective growth of the medium-sized particles is possible by repeating a set of "small dose implantation" and "moderate annealing", and to optimize implantation, annealing and repetition conditions.1.A sample with a dose of 1.1E17 ions/cm2 was annealed isochronally in vacuo at temperatures in a range of 150-600℃. It was found that small particles less than 〜3nm are integrated into medium particles of 3-5 nm by a moderate annealing (below 300℃, 〜1h). As a result, rater-particle spacings are enlarged so that the zero-field resistance of the sample is increased.2.Medium-sized particles are confirmed to be grown selectively in a sample with a total dose of 1.1E17 ions/cm2 prepared by a 2-step implantation. The MR ratio of the sample is increased by a factor of 1.4 as compared with that of a sample implanted at once.3.An additional third implantation to a total dose of 1.5E17 ions/cm2 into the above sample resulted in a particle size distribution identical to that observed in a sample implanted at once.4.When a dose for each step is decreased, the critical dose above which formation of large particles becomes dominant is slightly increased, and the zero-field resistance of the sample with the maximum MR ratio is drastically reduced, though no significant improvement is observed in the MR ratio.5.No clear difference was observed for different initial doses.6.It was suggested from the change of the zero-field resistance that the optimum annealing temperature (or time) depends on the accumulated dose in a sample at that step and therefore it is most important parameter in the optimization process.

对于粒状隧道磁阻材料，希望中等大小的超顺磁性细颗粒尽可能密集地分散在绝缘体基体中。本研究旨在通过重复一组“小剂量注入”和“适度退火”来实现中等大小粒子的选择性生长，并对注入、退火和重复条件进行优化。在150 ~ 600℃的真空条件下，对剂量为1.1E17 ions/cm2的样品进行等时退火。结果表明，在300℃以下、~ 1h的中等退火条件下，小于~ 3nm的小颗粒被整合为3 ~ 5 nm的中等颗粒。结果，粒子间距增大，使样品的零场电阻增大。在两步注入制备的总剂量为1.1E17离子/cm2的样品中，确定了中等大小颗粒的选择性生长。与一次性植入的样品相比，该样品的磁共振比增加了1.4倍。再以1.5E17离子/平方厘米的总剂量向上述样品中注入第三次，其颗粒大小分布与一次注入样品中观察到的相同。当每一步的剂量降低时，大颗粒形成占主导地位的临界剂量略有增加，MR比最大的样品的零场电阻急剧降低，但MR比没有明显改善。不同初始剂量无明显差异。从零场电阻的变化可以看出，最佳退火温度（或时间）取决于该步骤样品中的累积剂量，因此它是优化过程中最重要的参数。

项目成果

Analysis of Fe state in Fe-Al-O granular layers/films by conversion electron Mossbauer spectroscopy with applied magnetic fields

外加磁场下的转换电子穆斯堡尔谱分析 Fe-Al-O 颗粒层/薄膜中的 Fe 态

• 发表时间: 2005
• 期刊: J.Mossbauer Spectroscopy Res.Grope (in Japanese) 6
• 作者: T.Toriyama;H.Wakabayashi;J.Iwasaki;I.Sakamoto;N.Hayashi
• 通讯作者: N.Hayashi

Size control α-Fe fine particles by multi-step implantation of Fe ions into α-Al_2O_3

通过Fe离子多步注入α-Al_2O_3控制α-Fe细颗粒的尺寸

• 发表时间: 2005
• 期刊: Proceedings of the specialist research meeting on new developments in solid state physics with probes of radiation and nuclei (in Japanese) KURRI-KR-118
• 作者: H.Wakabayashi;S.Mochizuki;T.Toriyama;I.Sakamoto;N.Hayashi
• 通讯作者: N.Hayashi

Size distribution control of alpha-iron nano-particles in iron-implanted Al_2O_3 by multi-step implantation combined with moderate annealing

多步注入结合适度退火控制铁注入Al_2O_3中α-铁纳米粒子的尺寸分布

• 发表时间: 2004
• 期刊: Trans.Mater.Res.Soc.Jpn. 29
• 作者: T.Toriyama;H.Wakabayashi;J.Iwasaki;I.Sakamoto;N.Hayashi;若林 英彦;山城 将人;S.Mochizuki
• 通讯作者: S.Mochizuki

電磁石を用いた磁場印加内部転換電子メスバウアー分光(CEMS)システム

使用电磁铁的磁场应用内转换电子穆斯堡尔能谱 (CEMS) 系统

• 发表时间: 2005
• 期刊: 第52回応用物理学関係連合講演会 講演予稿集 No.2
• 作者: T.Toriyama;H.Wakabayashi;J.Iwasaki;I.Sakamoto;N.Hayashi;若林 英彦;山城 将人
• 通讯作者: 山城 将人

繰り返しイオン注入によるFeイオン注入α-Al_2O_3中のα-Fe微粒子の粒径制御

反复离子注入对Fe离子注入α-Al_2O_3中α-Fe细颗粒的粒径控制

• 发表时间: 2004
• 期刊: 「放射線と原子核をプローブとした物性研究の新展開」専門研究会報告(V),KURRI-KR 106
• 作者: T.Toriyama;H.Wakabayashi;J.Iwasaki;I.Sakamoto;N.Hayashi;若林 英彦;山城 将人;S.Mochizuki;A.Abuliemu;若林 英彦;若林 英彦
• 通讯作者: 若林 英彦