2021 Fiscal Year Research-status Report
Exploring novel graphene/ferrimagnetic Heusler alloy heterostructures for spin-photonic applications
| Project/Area Number |
21K20508
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| Research Institution | National Institutes for Quantum Science and Technology |
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Principal Investigator |
BENTLEY PHILLIP.DAVID 国立研究開発法人量子科学技術研究開発機構, 高崎量子応用研究所 先端機能材料研究部, 博士研究員 (40906260)
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| Project Period (FY) |
2021-08-30 – 2023-03-31
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| Keywords | Ferrimagnetism / Heusler Alloys / PMA / Small Magnetic Moment / Cubic Full-Heusler / Half-metal / MRAM / New Materials |
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| Outline of Annual Research Achievements |
Successfully fabricated for the first time high-quality cubic ferrimagnetic full-Heusler Mn2FexGa (MFG) thin films which show strong perpendicular magnetic anisotropy, have small associated magnetic moments, and are robust down to thicknesses as low as 5 nm. Initially MFG samples with varying iron concentration (x) were grown on substrates of MgO before it was then realised that growing these same thin films on a Cr buffer layer significantly aided the growth of cubic MFG and led to high-quality single-crystalline MFG. Cubic MFG presents itself as a promising material for the development of next-generation spintronic devices such as magnetic random-access memory (MRAM) and the results obtained so far thanks to the help of this grant have led to a publication currently in preparation.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
So far a significant number of samples have been produced exploring cubic and tetragonal MFG. The difficulties associated with exploring a new material/system (cubic MFG) have been a challenge for the principle researcher and this led initially to some minor delays. However, overall the first year of the plan has gone according to schedule with all the main objectives having been achieved. With now a much better understanding of cubic MFG, more significant progress towards exploring this system can be made. For example probing the surface density of states (SDOS) of MFG using spin-polarised metastable de-excitation spectroscopy (SPMDS), exploring growth of graphene on these cubic MFG thin films, and probing the SDOS at the interface of these heterostructures using SPMDS.
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| Strategy for Future Research Activity |
With the first year of this plan having gone to schedule, the aim is to (1) explore the surface density of states (SDOS) of optimal cubic MFG thin films using spin-polarised metastable de-excitation spectroscopy (SPMDS), (2) grow graphene and other 2D materials on top of these optimal MFG thin films using chemical vapour deposition and molecular beam epitaxy, (3) explore the SDOS at the interface of these novel heterostructures using SPMDS and further optimise the preparation conditions and properties of these structures. The results of these graphene/cubic MFG heterostructures will not only provide a greater understanding of the performance of next-generation spintronic devices but hopefully also lead to the realisation of highly-efficient magnetic random-access memory.
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| Causes of Carryover |
The first year of funding and spending of these funds went almost as planned. The second year of funding will be used to purchase the following consumables and items in the following year: (1) MgO(001) substrates to grow graphene/MFG heterostructures on. (2) Targets, single and alloy for the generation of MFG. (3) Gases such as Helium in order to perform SPMDS, Nitrogen and Argon gas for performing experiments, and organic gases to grow graphene and other 2D materials on top of MFG. (4) Sputter guns for magnetron sputtering of MFG and growing the MFG thin films in situ in the SPMDS system.
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