| 研究実績の概要 |
The JSPS DC2 holder (Ye Du), during the past fiscal year, has published 2 first-authored peer-reviewed papers in internationally influential scientific journals (Applied Physics Letters, IEEE Transactions on Magnetics); he has made 2 oral presentations in major international conferences (IEEE International Magnetics Conference 2015, Beijing-China and 13th Joint MMM/Intermag Conference 2016, San Diego-USA); he has received 2 oral presentation awards from international/domestic conferences (Best oral presentation award (finalist) at the 13th Joint MMM/Intermag Conference, San Diego-USA and JSAP oral presentation award at the 63rd JSAP spring meeting, Tokyo-Japan); also, he and his co-workers have applied for 2 patents (one US/international and one domestic).
Specifically, Ye Du has conducted research on the topic of current-perpendicular-to-plane magneto-resistance (CPP-GMR). His work on the <001> textured poly-crystalline CPP-GMR pseudo spin valves using a conductive Mg-Ti-O buffer layer has shown relatively large MR output as well as favorable smooth multi-layer interfaces. The Mg-Ti-O buffer layer is a promising choice to fabricate <001> textured CPP-GMR devices. On the other hand, his work on the novel AgZn spacer has demonstrated record-high CPP-GMR output through the ordering enhancement of Heusler compound that dramatically increases its bulk spin polarization. The work has shown an alternative way to substantially enhance the chemical ordering of the Heusler alloy layer, and presents experimental evidence for the realization of ultrahigh areal density hard disk drives.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
The JSPS DC2 holder (Ye Du), during the past fiscal year, has conducted current-perpendicular-to-plane giant magneto-resistance (CPP-GMR) based research according to the research proposal he submitted about one year ago.
His work on the Mg-Ti-O buffered poly-crystalline CPP-GMR presents a new perspective on the method of fabricating the <001> textured Heusler-alloy-based thin films and their corresponding devices. The relatively large MR output and the desirable interfacial smoothness are distinct advantages that might enables this work to be applied to read sensor fabrication.
His work on the CPP-GMR with Ag-Zn spacer material shows an alternative way (through Zn diffusion out of the Heusler layers) to enhance the chemical ordering of the Heusler alloy layers, thereby substantially improving the output performance in the CPP-GMR devices. This work presents experimental evidence for the realization of read head in future ultrahigh density hard disk drives (> 2 Tbit/in2).
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| 今後の研究の推進方策 |
As for the future work, we are planning to study the magneto-resistance effect using transparent oxide spacer materials to increase the interfacial resistance at the Heusler/spacer interfaces, so as to further increase the MR output of the devices and to enhance their electrical endurance against the spin transfer torque that occurs to destabilize the magnetization at very large current densities. Also, the underlying physics of the spin transfer torque or its related phenomenon will be studied as an extension. These works will both be of merits for physics-level fundamental understanding and practical applications. We believe that our future work is going to bring great impact onto the applied physics or materials science as we have done in the past year.
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