Ultrafast Spintronics: Dynamics of the Photoisomerization-Induced Spin–Charge Excited-State (PISCES) Mechanism in Spirooxazine-Based Photomagnetic Materials
| Autor: | Adam J. Jenkins, Delmar S. Larsen, Natia L. Frank, Aiko Kurimoto, L. Tyler Mix, Ziliang Mao |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Photoisomerization Spin states Spintronics chemistry.chemical_element 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences 0104 chemical sciences Magnetization Photochromism chemistry Excited state General Materials Science Physical and Theoretical Chemistry 0210 nano-technology Cobalt Visible spectrum |
| Zdroj: | The Journal of Physical Chemistry Letters. 9:5351-5357 |
| ISSN: | 1948-7185 |
| DOI: | 10.1021/acs.jpclett.8b02166 |
| Popis: | The optical control of spin state is of interest in the development of spintronic materials for data processing and storage technologies. Photomagnetic effects at the single-molecule level have recently been observed in the thin film state at 300 K in photochromic cobalt dioxolenes. Visible light excitation leads to ring-closure of a photochromic spirooxazine bound to a cobalt dioxolene, which leads to generation of a high magnetization state. Formation of the photomagnetic state occurs through a photoisomerization-induced spin-charge excited-state process and is dictated by the spirooxazine ligand dynamics. Here, we report a mechanistic investigation by ultrafast spectroscopy in the UV-vis region of the photochemical ring-closing process in the parent spirooxazine, azahomoadamantylphenanthroline spirooxazine, and the photomagnetic spirooxazine cobalt-dioxolene complex. The cobalt appears to stabilize a photomerocycanine transient intermediate, presumably the TCC isomer, formed along the ground-state potential energy surface (PES). Structural changes associated with the TCC isomer induces formation of the high-spin Co(II) form, suggesting that magnetization dymanics can occur along the excited-state PES, leading to ultrafast switching on the ps time scale. We demonstrate the full ring closure of the spiro-oxazine ligand is not required to switch magnetization states which can be induced with a higher yielding isomerization reaction. The ability of this system to undergo optically induced spin state switching on the ps time scale in the solid state makes it a promising canididate for resistive nonvolatile memory technologies. |
| Databáze: | OpenAIRE |
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