Magnetic fingerprint of individual Fe4 molecular magnets under compression by a scanning tunnelling microscope

• Published in: Nature communications 2015-09, Vol.6 (1), p.8216-8216, Article 8216
• Main Authors: Burgess, Jacob A.J., Malavolti, Luigi, Lanzilotto, Valeria, Mannini, Matteo, Yan, Shichao, Ninova, Silviya, Totti, Federico, Rolf-Pissarczyk, Steffen, Cornia, Andrea, Sessoli, Roberta, Loth, Sebastian
• Format: Article
• Language: English
• Subjects: 119/118; 639/766/119/997; 639/766/25; 639/766/36; 639/766/930/328; Humanities and Social Sciences; multidisciplinary; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms9216

Single-molecule magnets (SMMs) present a promising avenue to develop spintronic technologies. Addressing individual molecules with electrical leads in SMM-based spintronic devices remains a ubiquitous challenge: interactions with metallic electrodes can drastically modify the SMM’s properties by charge transfer or through changes in the molecular structure. Here, we probe electrical transport through individual Fe 4 SMMs using a scanning tunnelling microscope at 0.5 K. Correlation of topographic and spectroscopic information permits identification of the spin excitation fingerprint of intact Fe 4 molecules. Building from this, we find that the exchange coupling strength within the molecule’s magnetic core is significantly enhanced. First-principles calculations support the conclusion that this is the result of confinement of the molecule in the two-contact junction formed by the microscope tip and the sample surface. The incorporation of single-molecule magnets into spintronic devices is often hindered by electronic or structural modifications. Here, the authors demonstrate how confinement of Fe 4 molecules in junctions between a Cu 2 N substrate and a scanning microscope tip enhances intra-molecular exchange interaction.