2017 Fiscal Year Annual Research Report
Thin films and devices based on fully compensated half-metallic ferrimagnetic materials
| Project/Area Number |
17H06513
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| Research Institution | Tohoku University |
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Principal Investigator |
Ouardi Siham 東北大学, 材料科学高等研究所, 助手 (40807591)
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| Project Period (FY) |
2017-08-25 – 2018-03-31
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| Keywords | spintronics / Heusler alloys / ferrimagnets / Half-metals |
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| Outline of Annual Research Achievements |
The goal of the project is to grow and extensively investigate the thin films of the new class of material: fully compensated half-metallic ferrimagnets Mn1.5FeV0.5Al. Final goal is to create novel magnetic tunnel junctions with this new material for advanced spintronic applications.
We succeeded, for the first time, to grow epitaxial single-crystalline Mn1.5FeV0.5Al thin films with highly L21-ordered Heusler structure and improved their half-metallicity. All the samples were prepared using an ultrahigh vacuum magnetron sputtering system. With increasing the substrate temperature, the intensity of diffraction peaks (004) was enhanced, and the (002) superlattice diffraction peak from the B2 structure appeared for the films. We also observed (111) diffraction peak due to L21 chemical ordering. The epitaxial relationship of Mn1.5FeV0.5Al (001)[100]//MgO(001)[110] was found.
Then we investigated the anomalous Hall effect (AHE) for the film. The film exhibited a Neel P-type ferrimagnetic character in AHE, where the magnetic moment of the antiparallel aligned sublattices is always larger in one direction than in the opposite one and no compensation point is obtained. We also examined the half-metallicity of the films using anisotropic magnetoresistance (AMR). A negative AMR ratio was observed at 5 K and a magnetic field of 4 T. This negative sign of AMR proved the half-metallicity of the films, as generally discussed in other half-metallic Heusler alloys. The results demonstrated that the materials is promising for magnetic tunnel junctions for advanced spintronic applications.
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| Research Progress Status |
29年度が最終年度であるため、記入しない。
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| Strategy for Future Research Activity |
29年度が最終年度であるため、記入しない。
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