Weakly Interacting Molecular Spins in On‐Surface Synthesized Nanoclusters on a Graphene Oxide Nanosheet

Abstract

AbstractWith an average diameter of ≈2 nm, on‐surface synthesized amino‐ferrocene nanoclusters are chemisorbed onto a graphene oxide nanosheet, where their Fe ions are in an S = 5/2 high‐spin state. In this two‐dimensional (2D) nanomaterial, the molecular spins in a given nanocluster are weakly magnetic dipole interacting. It generates spin correlations and slow dynamics accessible by magnetic susceptibility and Mössbauer spectroscopy at a temperature where the magnetic anisotropy is negligible. Magnetic simulations show that minimizing their magnetic dipole energies produces spatially entangled structures of the spin orientations under thermal fluctuations at T ≲ 15 K and that the structures behave like a spin liquid. The competition between the formation of the structures and their thermal destruction generates slow dynamics. The ability to create emergent functionalities from dense stacks of weakly interacting magnetic molecules in a 2 nm space paves the way for new designs of an ultra‐compact building block and a functional component in 2D spintronic and neuromorphic devices.