Coexistence and interconvertibility of ferromagnetic and antiferromagnetic phases in the single crystal of Mn$_3$ single-molecule magnet

TL;DR

This study reveals reversible coexistence of ferromagnetic and antiferromagnetic phases in Mn$_3$ single-molecule magnets, modulated by oxidation-reduction processes affecting molecular structure and intermolecular interactions.

Contribution

It demonstrates the reversible control of magnetic phases in Mn$_3$ molecules through structural modifications induced by oxidation and reduction.

Findings

Coexistence of ferromagnetic and antiferromagnetic phases observed.

Molecular structure changes reversibly with oxidation-reduction.

Magnetic properties are influenced by methyl group presence.

Abstract

We report the coexistence of ferromagnetic and antiferromagnetic phases in the single crystal of Mn$_3$ single-molecule magnet. The coexistent state appears within a certain period of time in the progress of either oxidation or reduction during a reversible oxidation-reduction process, when the sample is exposed in the air (oxygen) or the methyl vapor. We noticed an apparent change in the molecular structure, which is also reversible in terms of that the methyl group is dropped or added to the molecules during the oxidation or reduction. The absence or presence of the methyl group in the molecules exert an essential impact upon the intermolecular exchange interaction, and the ferromagnetic phase comes from the heterogenous intermolecular bonds between pairs of molecules of which one molecule has a methyl group whereas the other has lost the methyl group. The reversible change in molecular structure suggests the magnetic structure of Mn$_3$ might be designed and modulated at molecular scale, which implies Mn$_3$ has a great application potential.