成果報告書詳細
管理番号20100000001128
タイトル*平成21年度中間年報 スピントロニクス不揮発性機能技術プロジェクト(2)
公開日2010/10/26
報告書年度2009 - 2009
委託先名国立大学法人東北大学
プロジェクト番号P06016
部署名電子・情報技術開発部
和文要約和文要約等以下本編抜粋:1. 研究開発の内容及び成果等 東北大学では、超高集積で高速な不揮発性メモリとして期待されるスピンRAM のための基盤技術を開発する為に(1)CMOSと整合するTMR素子の開発の研究を行なった。また、トランジスタへの不揮発性機能の付与を目指して、(2)スピン能動素子設計技術の研究を行った。平成21年度の成果を以下の通りまとめた。いずれの研究テーマについても、当初の研究計画どおりに進展が見られ、次年度に更に研究を進めることで、最終目標の実現が可能であると考えられる。
英文要約Research report in 2009 (Tohoku University)
In order to develop fundamental technologies for spin transfer torque
random access memory (STT-RAM), which is expected to be Gbit and very
fast non-volatile memory as the next generation memory, and also to
realize non-volatile transistor, the following researches have been
carried out in Tohoku University:
1.Development of TMR device for integration with CMOS transistor
2.Development of Spin transistor with Half-metal electrodes.
These researches and developments were in progress as we planed originally,
and the final goal of this project will be achieved by the research planed
in the next year. We summarized the results of research done in 2009 as follows.
1.Development of TMR device for integration with CMOS transistor
In 2008, we developed angular and field variation measurement technique of optical pump-probe method, which enabled us to evaluate magnetic damping
constant in various high perpendicular magnetic anisotropy (PMA) materials.
In 2009, we improved this optical pump-probe set-up further so as to measure under much higher magnetic field than that in 2008. Using this technique, we obtained magnetic damping constant in various materials, which helped significantly to develop high PMA material with low magnetic damping for TMR devices.
Furthermore, we gained the information of damping mechanism from systematic investigation on various dependences of magnetic damping. This result will be able to help us to design a TMR device which shows stable performance and is integrated with CMOS transistor. We have also constructed rf-measurement set-up for characterization of magnetic damping in actual device structure, which will be investigated in detail in next year for achieving the development of TMR devices integrated with CMOS transistor.
2. Development of Spin transistor with Half-metal electrodes.
Research aims of this year are as follows;
1 To optimization of the composition for half-metal Heusler alloys,
2 To optimization of the structure of the transistor device and clarify the means to achieve 1000 on/off ratio,
3 To investigate the temperature dependence of the magnetic damping in the Heusler alloys systematically.
1 A very large TMR ratio of 1275%, which is the highest value in the MTJs using half-metal electrodes, was achieved at 2K by inserting a very thin CoFe layer into the Heusler alloy/MgO interface. In addition, a large TMR of 350% was also observed at room temperature.
2 We designed a new transistor device structure because the gate voltage efficiency was very low in the transistor device fabricated until the last year. The new transistor device was fabricated and a very large magnetic-on/off ratio of 350% was observed at 2K by optimizing micro-fabrication process. As a result, we found the means to achieve a 1000 on/off ratio.
3 The temperature dependence of the magnetic damping in the Co-based Heusler alloys was systematically investigated. We found that the magnetic damping relates to the half-metallicity in the Heusler alloys. This knowledge is very useful to clarify the origin of the temperature dependence of TMR effect.
ダウンロード成果報告書データベース(ユーザ登録必須)から、ダウンロードしてください。

▲トップに戻る