Directly probing spin dynamics in a molecular magnet with femtosecond time-resolution

Johan Olof Johansson, Ji-Wan Kim, Emily Allwright, David Rogers, Neil Robertson, Jean-Yves Bigot

Research output: Contribution to journalArticlepeer-review

Abstract / Description of output

We show that a vanadium-chromium Prussian Blue analogue, which is a room-temperature molecule-based magnet, displays a fast magnetic response on a femtosecond timescale that is due to the super-exchange interaction between the metal ions. This dynamics is obtained from femtosecond Faraday magneto-optical (MO) measurements, performed at 50 and 300 K. Exciting at the ligand-to-metal charge-transfer (LMCT) band results in the formation of the 2E excited state on the Cr ion via intersystem crossing (ISC) from the 4LMCT state in less than 250 fs. Subsequent vibrational relaxation in the 2E state occurs on a 0.78 ± 0.05 ps timescale at 50 K and 1.1 ± 0.1 ps at 300 K. The MO measurements can detect the formation of the 2E state on the Cr ion from the change in the super-exchange interaction taking place as a results of the corresponding spin flip associated with the formation of the 2E state. These studies open up a new avenue to study molecular magnets using a powerful method that is capable of directly probing spin dynamics on a sub-picosecond timescale in thin film environments.
Original languageEnglish
Pages (from-to)7061-7067
Number of pages7
JournalChemical Science
Volume7
Issue number12
Early online date1 Aug 2016
DOIs
Publication statusPublished - 1 Dec 2016

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