Ultrafast Spintronics in Photochromic Cobalt Switches

Photograph of the spirooxazine ring-closure reaction, resulting in a charge transfer spin transition at the Co center.
Photograph of the spirooxazine ring-closure reaction, resulting in a charge transfer spin transition at the Co center.

In a recent publication (Jenkins et al. Ultrafast Spintronics: Dynamics of the Photoisomerization-Induced Spin–Charge Excited-State (PISCES) Mechanism in Spirooxazine-Based Photomagnetic Materials), the Larsen Lab, in collaboration with the Frank Lab (U. Victoria) explored the primary photodynamics of a novel Co coordination complex that via the structural evolution of a modified spirooxazine ligand will induced long living spin states. The visible and NIR-IR photodynamics of the isolated spirooxazine ligand were compared with the full Co-III complex to demonstrate that the complex stabilizes the primary isomerization step in the ring-closing mechanism and the initial isomerization step is sufficient to induce the spin flip on the cobalt metal within a 2 ps timescale. This study demonstrates that optical spintronics can be extended into the ultrafast regime at several orders of magnitude faster switching dynamics than previously observed in existing semiconductor systems.

More information at https://pubs.acs.org/doi/10.1021/acs.jpclett.8b02166