Maximizing the magnetic anisotropy of Dy complexes by fine tuning organic ligands: A systematic multireference high-throughput exploration of over 30k molecules

TL;DR

This study systematically explores over 30,000 molecules to identify Dy complexes with enhanced magnetic anisotropy through organic ligand tuning, using high-throughput multireference ab initio calculations.

Contribution

It introduces a computational framework for screening and designing Dy complexes with improved magnetic properties via ligand modifications.

Findings

Identified molecules with over 1600 cm$^{-1}$ crystal field splitting, doubling previous records.

Achieved approximately 100% increase in magnetic anisotropy over reference compounds.

Demonstrated the effectiveness of automated high-throughput screening in discovering promising magnetic materials.

Abstract

The design of the coordination environment of magnetic ions is key to achieving properties such as large magnetic anisotropy and slow magnetic relaxation, but a systematic exploration of the relevant chemical space for these compounds is missing. Here, we automatically extract all entries of mononuclear Dy coordination complexes from crystallographic databases and use multireference ab initio methods to compute their magnetic anisotropy. In addition, we generate and simulate magnetic anisotropy for 25k new molecules with the general formula [Dy(H$_2$O)$_5$L$_2$]$^{n-}$ and pentagonal bipyramidal coordination geometry, a motif selected as very promising. While no molecule with record magnetic anisotropy is serendipitously identified in crystallography databases, molecules with crystal field splittings over 1600 cm$^{-1}$ are identified by systematically exploring new organic ligands. This corresponds to a ~100% increase of magnetic anisotropy over the reference compound, ~30% over any known pentagonal bipyramidal Dy complex, and approaching record values of pseudo bi-coordinated Dy ions. This study demonstrates that the fine-tuning of Dy's second coordination sphere by organic ligands design can significantly improve magnetic anisotropy and that automated computational screening is key to accelerating this chemically non-intuitive process.