# 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.

## Key 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.