| Project/Area Number |
12640363
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体物性Ⅱ(磁性・金属・低温)
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| Research Institution | RIKEN (The Institute of Physical and Chemical Research) |
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Principal Investigator |
YAMAZAKI Hiroki RIKEN, Magnetic Materials Lab. , Senior Research Scientist, 磁性研究室, 先任研究員 (00271528)
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| Co-Investigator(Kenkyū-buntansha) |
田中 良和 理化学研究所, 磁性研究室, 先任研究員 (90250109)
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| Project Period (FY) |
2000 – 2002
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| Project Status |
Completed (Fiscal Year 2002)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2000: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | artificial lattice / magnetic anisotropy competition / exchange-coupling competition / heavy rare-earth metal / iron fluoride / neutron diffraction / frustration / ultra-thin film / 磁性人工格子 / 超交換相互作用 / 磁気異方性 / 競合 / 次元クロスオーバー / 絶縁体人工格子 / 磁性競合系 / 2次元磁性体 / エピタキシャル成長 |
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| Research Abstract |
In this study, fabrication of the magnetic competing, with respect to magnetic antisotropy or exchange-coupling, systems was performed using artificial superlattices. Their magnetic properties were investigated in order to find out novel magnetic phases due to the magnetic competition. The magnetic systems with the competition in magnetic anisotropy were realized in the single-crystal Er/Tb superlattices grown parallel to the c-axis of hcp structure. Neutron diffraction study revealed that, as a function of temperature, the spin component parallel to the c-axis undergoes the same sequence including the Neel and Curie temperatures as bulk Er, while the component in the basal plane retains a helical ordering at higher temperatures up to 130K, which is more than twice the corresponding temperature of bulk Er. We argued that the basal-plane ferromagnetic ordering of the adjacent Tb layers enhanced the development of the basal-plane ordering in the Er layers. In order to study the magnetic systems with the competition in exchange-coupling, fluoride superlattices of FeF_2/ZnF_2 were prepared on single-crystal substrates. In addition to close structural characterization, dependence of the Neel temperature on the thickness of the FeF_2(001) and (110) ultra-thin layers was investigated. The observed periodic variations of the Neel temperature with a period of 1 atomic monolayer were discussed in terms of an interface-topographical frustration due to the competing exchange-coupling of J_2 and J_3. These superlattices can be regarded as "controlled competing systems" in contrast to the bulk dilute system of Fe_xZn_<1-x>F_2.
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