2006 Fiscal Year Final Research Report Summary
Study of interface structure of magnetic nano-super-lattice by azimuthal scan reflection high-energy electron diffraction
| Project/Area Number |
17360016
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thin film/Surface and interfacial physical properties
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| Research Institution | Tohoku University |
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Principal Investigator |
ABUKAWA Tadashi Tohoku University, Institute for Multidisciplinary Research for Advanced Materials, Associate Professor, 多元物質科学研究所, 助教授 (20241581)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Electron Diffraction / Interface structure / Tunnel magnet-resistance / Giant Magneto-resistance / Roughness |
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| Research Abstract |
It is known that a magneto-resistance of GMR or TMR device is greatly affected by an interface structure and structural roughness between a ferromagnetic layer and non-magnetic layer. The aim of this study is to understand roles of the interface for the resistance by studying its structure and roughness with an azimuthal scan reflection high-energy electron diffraction (Φ-scan RHEED). At first, an apparatus for Φ-scan RHEED was assembled from an UHV chamber, an energy filter, an electron gun and a 5-axes manipulator. In addition, an e-beam evaporator, a 3KV ion gun and a hemispherical electron analyzer was attached to the apparatus. Thus an apparatus which is capable of fabricating magnetic super-layers as well as measuring Φ-scan RHEED have been completed by this study.
The apparatus was first applied to the interface of Fe deposited Si(111) surface. Although most of Fe silicides formed on the Si(111) surface are not ferromagnetic, it is very important to understand its interface structure for fabricating magnetic devises on Si substrate. Fe silicides were fabricated under various conditions, and their surface and interface structures has been investigated by Φ-scan RHEED. It was found that a-FeSi_2 was formed when Fe atoms reacted with Si on Si surface. On the other hand, P-FeSi_2 grew when Fe atoms reacted with Si at a solid Fe/Si interface. As a initial stage of Fe/MgO/Fe TMR structure on Si substrate, MgO epitaxial growth was investigated by 4-scan RHEED. It was unexpectedly found that MgO epitaxially grew on Si(111) with different orientations depending on growth conditions. The result indicates a way to fabricate a single orientation of MgO layer. Unfortunately, any interface of GMR or TMR devices have not been investigated in this study. However, they are under preparation and will be investigated soon.
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