Controlling the magnetic exchange coupling in hybrid heterojunctions via spacer layers of π -conjugated molecules

Quentin Arnoux 1, 2 Camille Blouzon 3 Dongzhe Li 4 Yannick Dappe 4 Alexander Smogunov 4 Pierre Bonville 3 Ludovic Tortech 1, 2 Jean-Baptiste Moussy 3
1 LICSEN - Laboratoire Innovation en Chimie des Surfaces et NanoSciences
NIMBE UMR 3685 - Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M)
3 LNO - Laboratoire Nano-Magnétisme et Oxydes
SPEC - UMR3680 - Service de physique de l'état condensé, IRAMIS - Institut Rayonnement Matière de Saclay
4 GMT - Groupe Modélisation et Théorie
IRAMIS - Institut Rayonnement Matière de Saclay, SPEC - UMR3680 - Service de physique de l'état condensé
Abstract : Mastering and understanding the magnetic couplings between magnetic electrodes separated by organic layers are crucial for developing new hybrid spintronic devices. We study the magnetic exchange interactions in organic-inorganic heterojunctions and unveil the possibility of controlling the strength of the magnetic exchange coupling between two ferromagnetic electrodes across π-conjugated molecules’ (α-sexithiophene or para-sexiphenyl) ultrathin film. In Fe3O4/π-conjugated molecules/Co magnetic tunnel junctions, an antiferromagnetic interlayer exchange coupling with variable strength is observed according to the nature of the aromatic rings (thiophene or phenyl groups). The underlying physical mechanism is revealed by ab initio calculations relating the strength of magnetic coupling to the spin moment penetration into a molecular layer at the molecule/Co interface. The prospect that magnetic coupling between two ferromagnetic electrodes can be mediated and tuned by organic molecules opens different perspectives in the way magnetization of organic tunnel junctions or spin valves can be driven.
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https://hal-cea.archives-ouvertes.fr/cea-02091363
Contributor : Serge Palacin <>
Submitted on : Friday, April 5, 2019 - 4:11:05 PM
Last modification on : Thursday, July 4, 2019 - 11:00:08 AM

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Quentin Arnoux, Camille Blouzon, Dongzhe Li, Yannick Dappe, Alexander Smogunov, et al.. Controlling the magnetic exchange coupling in hybrid heterojunctions via spacer layers of π -conjugated molecules. Physical Review B : Condensed matter and materials physics, American Physical Society, 2019, 99 (14), pp.144405. ⟨https://link.aps.org/doi/10.1103/PhysRevB.99.144405⟩. ⟨10.1103/PhysRevB.99.144405⟩. ⟨cea-02091363⟩

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