Record High Magnetic Anisotropy in Chemically Engineered Iridium Dimer

TL;DR

This study demonstrates that chemically engineered Iridium dimers can achieve record-high magnetic anisotropy energies, promising for stable magnetic data storage at room temperature.

Contribution

We show that attaching halogen atoms to Iridium dimers significantly enhances their magnetic anisotropy energy, providing a new approach for designing stable magnetic nanostructures.

Findings

Ir2 dimer has an intrinsic MAE of 77 meV.

Halogen attachment increases MAE to 223-294 meV.

Modification of energy levels via halogen bonding explains the enhancement.

Abstract

Exploring giant magnetic anisotropy in small magnetic nanostructures is of both fundamental interest and technological merit for information storage. To prevent spin flipping at room temperature due to thermal fluctuation, large magnetic anisotropy energy (MAE) over 50 meV in magnetic nanostructure is desired for practical applications. We chose one of the smallest magnetic nanostructures-Ir2 dimer, to investigate its magnetic properties and explore possible approach to engineer the magnetic anisotropy. Through systematic first-principles calculations, we found that the Ir2 dimer already possesses giant MAE of 77 meV. We proposed an effective way to enhance the MAE of the Ir2 dimer to 223~294 meV by simply attaching a halogen atom at one end of the Ir-Ir bond. The underlying mechanism for the record high MAE is attributed to the modification of the energy diagram of the Ir2 dimer by the additional halogen-Ir bonding, which alters the spin-orbit coupling Hamiltonian and hence the magnetic anisotropy. Our strategy can be generalized to design other magnetic molecules or clusters with giant magnetic anisotropy.