Capturing Ultrafast Spin Dynamics in Single-Molecule Magnets Using Femtosecond X-ray Emission Spectroscopy

TL;DR

Researchers used ultrafast X-ray techniques to study how single-molecule magnets change their spin states after laser excitation, which could help develop faster data storage.

Contribution

The study introduces femtosecond X-ray emission spectroscopy as a novel method to probe ultrafast spin dynamics in single-molecule magnets.

Findings

Femtosecond X-ray emission spectroscopy reveals Jahn–Teller distorted structure switching in Mn(acac)3 after photoexcitation.

Spin state distributions in Mn3 are observed within 100 fs using Kβ signals.

The technique highlights the need for multi-spectrum probes to understand exchange-coupled complexes.

Abstract

Achieving ultrafast
photomagnetic switching of single-molecule
magnets (SMMs) could lead to simultaneous fast and dense data storage
devices. To facilitate this, a thorough understanding of the ultrafast
dynamics emerging after ultrashort laser pulse excitation is essential.
However, the complex nature of these materials means there is a lack
of established experimental techniques that can probe the spin dynamics
in SMMs. Herein, we perform femtosecond time-resolved Mn K-edge X-ray
emission spectroscopy on a Mn(III)-based trinuclear SMM (Mn3) and the model system Mn(acac)3. The spectral changes
of Mn(acac)3 are consistent with switching between Jahn–Teller
distorted structures expected after photoexcitation. A similar result
is observed for Mn3; however, the Kβ signal also
reveals insight into the distribution of spin states populated within
100 fs. The importance of using probes across the electromagnetic
spectrum to gain a thorough understanding of the dynamics of exchange-coupled
complexes is highlighted.

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