2023 Fiscal Year Research-status Report
Developing novel spintronic devices by using stackable crystalline membranes
| Project/Area Number |
23KJ1239
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| Research Institution | Kyoto University |
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Principal Investigator |
SHEN YUFAN 京都大学, 理学研究科, 特別研究員(DC2)
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| Project Period (FY) |
2023-04-25 – 2025-03-31
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| Keywords | Ferroelectricity / Freestanding Membranes / Hafnia |
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| Outline of Annual Research Achievements |
My project is to fabricate ferroelectric oxide freestanding membranes and integrate them into limit-free multiferroic electronic devices, realizing electrical performance controlled by electrical and magnetic fields.
During this project year, I stabilized ferroelectric hafnia thin films epitaxially by using pulse laser deposition, the mechanism of which is also clarified.
Furthermore, I exfoliated the ultrathin hafnia membranes down to 1 nm and confirmed the survival of ferroelectricity in this atomically thin oxide membrane, verifying the scale-free ferroelectricity in hafnia. The related work is under review currently and this work validates the possible limit-free multiferroic electronic devices based on these ultrathin membranes.
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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
The research aim for the first project year is to develop damage-free exfoliation method for fabricating freestanding membranes and characterize their ferroelectricity. During the past one year, I have accomplished my project goal for the first year.
During the past year, after stabilizing the hafnia epitaxial thin films, I developed a method to exfoliate them from the substrate without largely deteriorating the hafnia's crystallinity. Using this method, an almost single-crystal hafnia freestanding membrane down to the atomic thickness (1-nm-thick) was fabricated, with switchable ferroelectric polarization at room temperature being confirmed.
These ultrathin thin ferroelectric hafnia membranes can be used for fabricaitng limit-free multiferroelectric devices in the next project year.
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| Strategy for Future Research Activity |
During the last project year, I will proceed to stack these freestanding ferroelectric ultrathin hafnia membranes with the perpendicularly magnetized thin films to fabricate the multiferroic electronic devices, and tailor the electrical performance of the devices by using both electrical and magnetic fields.
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