2021 Fiscal Year Research-status Report
超高密度メモリデバイスを実現する反強磁性異方性トンネル接合素子の創製
| Project/Area Number |
20K04569
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
温 振超 国立研究開発法人物質・材料研究機構, 磁性・スピントロニクス材料研究拠点, 主任研究員 (40784773)
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| Project Period (FY) |
2020-04-01 – 2023-03-31
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| Keywords | Antiferromagnetic films / Tunnel junctions |
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| Outline of Annual Research Achievements |
In the past fiscal year, more fabrication and measurements of antiferromagnetic-FeRh-based magnetic tunnel junctions were performed and the bipolar tunneling magnetoresistance was confirmed. The first principles calculations on the tunneling magnetoresistance effect in the FeRh/MgO/Fe stacks have been carried out. New antiferromagnetic materials, including IrMn-based noncollinear antiferromagnetic stacks, Cr/Fe-based synthetic antiferromagnetic structures, and RuO2 collinear antiferromagnetic films were also prepared. The deposition conditions of these antiferromagnetic thin films were optimized by characterizing the surface morphology and structures of these samples by atomic force microscope and X-ray diffraction. The best condition was achieved for high-quality antiferromagnetic films.
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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
We performed characterizations and optimizations for the antiferromagnetic (AFM) materials, as well as designed/engineered new AFM materials and related structures, which follows our research plans. Therefore, the project is progressing rather smoothly.
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| Strategy for Future Research Activity |
In the coming fiscal year, I will fabricate tunnel junction devices based on the optimized antiferromagnetic thin films. For examples, I plan to fabricate antiferromagnetic tunnel junctions with the following stacks, (1) Al2O3(0001)-substrate//Ru/Cu/NiFe/IrMn/MgO/Ru or CoFe/Cap, (2) TiO-substrate//RuO2/TiO/RuO2 or CoFe/Cap, (3) Al2O3(0001)-substrate//Ru/Cu/NiFe/PtMn/MgO/PtMn/Cap. The stacks of antiferromagnetic tunnel junctions will be patterned into nano- and micro-sized pillars by microfabrication techniques, including EB and UV lithography, Ar ion milling and lift off technique. Transport measurements, such as the magnetic field and voltage dependences of tunneling resistance, tunneling conductance, and magnetoresistance, will be carried out at room temperature and low temperatures.
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