Magnetic Excitation in Artificially Designed Oxygen Molecule Magnet

TL;DR

This study investigates magnetic excitations in oxygen molecules adsorbed in a microporous compound, revealing a dispersionless excitation at 7.8 meV explained by a spin dimer model, and discusses temperature-dependent anomalies related to magnetoelasticity.

Contribution

First experimental observation of magnetic excitation in adsorbed O$_2$ molecules using neutron scattering, with a spin dimer model explaining the data and insights into magnetoelastic effects.

Findings

Dispersionless excitation at 7.8 meV observed

Spin dimer model with 3.1 Å intradimer distance explains data

Anomalous temperature dependence linked to magnetoelasticity

Abstract

We performed inelastic neutron scattering experiment to study magnetic excitation of O$_2$ molecules adsorbed in microporous compound. The dispersionless excitation with characteristic intensity modulation is observed at $\hbar \omega = 7.8$ meV at low temperature. The neutron cross section is explained by spin dimer model with intradimer distance of 3.1 \AA . Anomalous behaviour in the temperature dependence is discussed in the context of enhanced magnetoelasticity in the soft framework of O$_2$ molecule.