Tuning the Magnetic Anisotropy of Lanthanides on a Metal Substrate by Metal–Organic Coordination

Abstract

Taming the magnetic anisotropy of lanthanides through coordination environments is crucial to take advantage of the lanthanides properties in thermally robust nanomaterials. In this work, the electronic and magnetic properties of Dy‐carboxylate metal–organic networks on Cu(111) based on an eightfold coordination between Dy and ditopic linkers are inspected. This surface science study based on scanning probe microscopy and X‐ray magnetic circular dichroism, complemented with density functional theory and multiplet calculations, reveals that the magnetic anisotropy landscape of the system is complex. Surface‐supported metal–organic coordination is able to induce a change in the orientation of the easy magnetization axis of the Dy coordinative centers as compared to isolated Dy atoms and Dy clusters, and significantly increases the magnetic anisotropy. Surprisingly, Dy atoms coordinated in the metallosupramolecular networks display a nearly in‐plane easy magnetization axis despite the out‐of‐plane symmetry axis of the coordinative molecular lattice. Multiplet calculations highlight the decisive role of the metal–organic coordination, revealing that the tilted orientation is the result of a very delicate balance between the interaction of Dy with O atoms and the precise geometry of the crystal field. This study opens new avenues to tailor the magnetic anisotropy and magnetic moments of lanthanide elements on surfaces.

Engineering Periodic Dinuclear Lanthanide‐Directed Networks Featuring Tunable Energy Level Alignment and Magnetic Anisotropy by Metal Exchange

“…Moreover, simulations of the polar angular dependence of the XMCD signal indicates that the magnetization presents a tilted easy axis, which is oriented at 50° with respect to the surface normal (see Figure S8, Supporting Information), being slightly closer to the surface plane, in agreement with the magnetization curves described above. These results are consistent with the recently reported magnetic behavior of dinuclear Er atoms, [13,41] whose easy axis was located in the transition between in-plane and out-of-plane.…”

“…Following this assumption, it should be expected that Er +3 would have a prolate charge density for large J z , whereas Dy +3 would display an oblate charge density for high values of J z . [13,41] In the rhombic Er-and Dy-DPBP networks, the coordination symmetry is the same. However, the XLD measurements, which peak orientation is well reproduced by the simulations (see Figure 3d-h), indicate that the charge densities of the metallic centers are inverted.…”

Towards large area surface functionalization with luminescent and magnetic lanthanoid complexes

“…The recorded XAS and XMCD for 2Si-1 and 2 show similar structures, coinciding with that expected for Dy 3+ ions. 33 The orbital moment (m L ), spin moment (m s ) and total moment (m TOT = m L + m s ) per ion were determined by the XAS and XMCD spectra using the corrected sum rules for the Dy 3+ ion. 34,35 The correction is required to account for the large jj mixing between the 3d 5/2 and 3d 3/2 core levels, on the one hand, and the contribution of the 〈T z 〉 magnetic dipole term, on the other hand.…”

Transformation of the coordination nanostructures of 4,4′,4′′-(1,3,5-triazine-2,4,6-triyl) tribenzoic acid molecules on HOPG triggered by the change in the concentration of metal ions

“… 15–17 Moreover, their composition, morphology and properties have been well proved, and have opened up specific and targeted application in the areas of chemical and materials sciences. 18,19 However, few studies have focused on regulating the coordination structures which involves changing the metal species for coordination, and more importantly, the concentrations of metal ions used to form the coordination structures.…”