Control of positive and negative magnetoresistance in iron oxide−iron nanocomposite thin films for tunable magnetoelectric nanodevices
| Autor: | Martin Nichterwitz, Darius Pohl, Sandra Schiemenz, Jonas Zehner, Sebastian T. B. Goennenwein, Shashank Honnali, Kornelius Nielsch, Sebastian Schneider, K. Leistner |
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| Rok vydání: | 2020 |
| Předmět: |
Materials science
Nanostructure Magnetoresistance Magnetism Voltage control of magnetism Voltage control Iron oxide Physics::Optics Nanotechnology 02 engineering and technology 010402 general chemistry 01 natural sciences 7. Clean energy Magnetite Condensed Matter::Materials Science chemistry.chemical_compound Materials Chemistry Electrochemistry Iron films Magneto-ionic control Spintronics Nanocomposite thin films Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 0104 chemical sciences Electronic Optical and Magnetic Materials chemistry 0210 nano-technology |
| Zdroj: | Dipòsit Digital de Documents de la UAB Universitat Autònoma de Barcelona ACS Applied Electronic Materials |
| Popis: | The perspective of energy-efficient and tunable functional magnetic nanostructures has triggered research efforts in the fields of voltage control of magnetism and spintronics. We investigate the magnetotransport properties of nanocomposite iron oxide/iron thin films with a nominal iron thickness of 5-50 nm and find a positive magnetoresistance at small thicknesses. The highest magnetoresistance was found for 30 nm Fe with +1.1% at 3 T. This anomalous behavior is attributed to the presence of Fe3O4-Fe nanocomposite regions due to grain boundary oxidation. At the Fe3O4/Fe interfaces, spin-polarized electrons in the magnetite can be scattered and reoriented. A crossover to negative magnetoresistance (−0.11%) is achieved at a larger thickness (>40 nm) when interface scattering effects become negligible as more current flows through the iron layer. Electrolytic gating of this system induces voltage-triggered redox reactions in the Fe3O4 regions and thereby enables voltage-tuning of the magnetoresistance with the locally oxidized regions as the active tuning elements. In the low-magnetic-field region ( |
| Databáze: | OpenAIRE |
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