Magnetic Hysteresis at 10 K in Single Molecule Magnet Self-Assembled on Gold.

Chia‐Hsiang Chen,Jan Dreiser,Fupin Liu,Emmanouil Koutsouflakis,Denis S Krylov,Alexander Fedorov,Philippe Ohresser,Eugen Weschke,Lukas Spree,Alexey A Popov,Fadi Choueikani,Georgios Velkos,Stanislav M Avdoshenko,Sebastian Schimmel,Bernd Büchner,Ariane Brandenburg

doi:10.1002/advs.202000777

Abstract

Tremendous progress in the development of single molecule magnets (SMMs) raises the question of their device integration. On this route, understanding the properties of low‐dimensional assemblies of SMMs, in particular in contact with electrodes, is a necessary but difficult step. Here, it is shown that fullerene SMM self‐assembled on metal substrate from solution retains magnetic hysteresis up to 10 K. Fullerene‐SMM DySc2N@C80 and Dy2ScN@C80 are derivatized to introduce a thioacetate group, which is used to graft SMMs on gold. Magnetic properties of grafted SMMs are studied by X‐ray magnetic circular dichroism and compared to the films of nonderivatized fullerenes prepared by sublimation. In self‐assembled films, the magnetic moments of the Dy ions are preferentially aligned parallel to the surface, which is different from the disordered orientation of endohedral clusters in nonfunctionalized fullerenes. Whereas chemical derivatization reduces the blocking temperature of magnetization and narrows the hysteresis of Dy2ScN@C80, for DySc2N@C80 equally broad hysteresis is observed as in the fullerene multilayer. Magnetic bistability in the DySc2N@C80 grafted on gold is sustained up to 10 K. This study demonstrates that self‐assembly of fullerene‐SMM derivatives offers a facile solution‐based procedure for the preparation of functional magnetic sub‐monolayers with excellent SMM performance.

Highlights

Tremendous progress in the development of single molecule magnets (SMMs) raises the question of their device integration
A prerequisite for potential nanodevice implementation of a given SMM is that its magnetic bistability demonstrated in bulk powder or crystal sample should be preserved on a substrate, which will serve as an electrode of a device.[4]
Because of the considerable remanence and coercivity found in its powder samples,[15] Dy2ScN@C80 was in focus of the earlier surface studies of endohedral metallofullerenes (EMFs)-SMMs, and magnetic properties of its www.advancedscience.com monolayers were studied by X-ray magnetic circular dichroism (XMCD) on Rh(111), h-BN|Rh(111), Au(111), Ag(100), and MgO(10 ML)|Ag(100).[12]

Summary

Introduction

Tremendous progress in the development of single molecule magnets (SMMs) raises the question of their device integration. In this work we use these advantages to prepare self-assembled sub-monolayer films (SAMs) of fullerenes DySc2N@C80 and Dy2ScN@C80 on Au(111) and achieve the highest temperature of magnetic hysteresis for SMMs on a metallic substrate.

Results

Conclusion