Bulk-Like Magnetic Signature of Individual Fe₄H Molecular Magnets on Graphene

Abstract

Single-molecule magnets (SMMs) incorporate key properties that make them promising candidates for the emerging field of spintronics. The challenge to realize ordered SMM arrangements on surfaces and at the same time to preserve the magnetic properties upon interaction with the environment is a crucial point on the way to applications. Here we employ inelastic electron tunneling spectroscopy (IETS) to address the magnetic properties in single Fe4 complexes that are adsorbed in a highly ordered arrangement on graphene/Ir(111). We are able to substantially reduce the influence of both the tunneling tip and the adsorption environment on the Fe4 complex during the measurements by using appropriate tunneling parameters in combination with the flat-lying Fe4H derivative and a weakly interacting surface. This allows us to perform noninvasive IETS studies on these bulky molecules. From the measurements we identify intermultiplet spin transitions and determine the intramolecular magnetic exchange interaction constant on a large number of molecules. Although a considerable scattering of the exchange constant values is observed, the distribution maximum is located at a value that coincides with that of the bulk. Our findings confirm a retained molecular magnetism of the Fe4H complex at the local scale and evaluate the influence of the environment on the magnetic exchange interaction.

Exceptionally High Blocking Temperature of 17 K in a Surface‐Supported Molecular Magnet

“…Here, sub-monolayers of Dy 2 @C 80 (CH 2 Ph) molecules were deposited on a graphene/Ir(111) substrate by employing the electrospray deposition (ESD) technique [32][33][34] (see Section 4 for further details). Our STM measurements show that the majority of molecules constitute ordered islands with only small amount of isolated molecules lying on the surface.…”

Electrospray Deposition and Magnetic Properties of Prototypical Molecular Magnets

“…Carefully adjusting tunneling and tip-approach parameters we previously performed IETS measurements on a large number of molecules to obtain reliable statistics, giving the possibility to quantitatively evaluate the impact of the magnetic field [78]. At the same time this procedure captures the variation of step energies that are present within the submonolayer.…”

Fulvalene as a platform for the synthesis of a dimetallic dysprosocenium single-molecule magnet

“…above the boiling point of liquid nitrogen, and elegant surface studies of some SMMs have demonstrated the singlemolecule origins of the hysteresis. 12 The advances made to date strengthen the motivation for further research into SMMs, particularly the exploration of new synthetic strategies that aim to increase the temperatures at which these materials function. Considerable effort has been invested into maximizing the effective energy barrier to reversal of the magnetization (U eff ) and the magnetic blocking temperature (T B ).…”

“…above the boiling point of liquid nitrogen, and elegant surface studies of some SMMs have demonstrated the single-molecule origins of the hysteresis. 12 …”