Exchange coupling inversion in a high-spin organic triradical molecule

• Published in: arXiv.org 2016-02
• Main Authors: Gaudenzi, R, Burzurí, E, Reta, D, I de P R Moreira, Bromley, S T, Rovira, C, Veciana, J, H S J van der Zant
• Format: Article
• Language: English
• Subjects: Antiferromagnetism; Coupling; Coupling (molecular); Exchanging; Magnetic properties; Nanotechnology devices; Organic chemistry; Thickness
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.1602.03678

The magnetic properties of a nanoscale system are inextricably linked to its local environment. In ad-atoms on surfaces and inorganic layered structures the exchange interactions result from the relative lattice positions, layer thicknesses and other environmental parameters. Here, we report on a sample-dependent sign inversion of the magnetic exchange coupling between the three unpaired spins of an organic triradical molecule embedded in a three-terminal device. This ferro-to-antiferromagnetic transition is due to structural distortions and results in a high-to-low spin ground state change in a molecule traditionally considered to be a robust high-spin quartet. Moreover, the flexibility of the molecule yields an in-situ electric tunability of the exchange coupling via the gate electrode. These findings open a route to the controlled reversal of the magnetic states in organic molecule-based nanodevices by mechanical means, electrical gating or chemical tailoring.