Exchange Biasing Single Molecule Magnets: Coupling of TbPc sub(2) to Antiferromagnetic Layers

• Published in: Nano letters Vol. 12; no. 11; pp. 5703 - 5707-5703-5707
• Main Authors: Rizzini, ALodi, Krull, C, Balashov, T, Mugarza, A, Nistor, C, Yakhou, F, Sessi, V, Klyatskaya, S, Ruben, M, Stepanow, S, Gambardella, P
• Format: Journal Article
• Language: English
• Published: 04-01-2012
• Subjects: Anisotropy; Antiferromagnetism; Bias; Deposition; Exchange; Magnetization; Magnets; Manganese; Nanostructure
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl302918d

We investigate the possibility to induce exchange bias between single molecule magnets (SMM) and metallic or oxide antiferromagnetic substrates. Element-resolved X-ray magnetic circular dichroism measurements reveal, respectively, the presence and absence of unidirectional exchange anisotropy for TbPc sub(2) SMM deposited on antiferromagnetic Mn and CoO layers. TbPc sub(2) deposited on Mn thin films present magnetic hysteresis and a negative horizontal shift of the Tb magnetization loop after field cooling, consistent with the observation of pinned spins in the Mn layer coupled parallel to the Tb magnetic moment. Conversely, molecules deposited on CoO substrates present paramagnetic magnetization loops with no indication of exchange bias. These experiments demonstrate the ability of SMM to polarize the pinned uncompensated spins of an antiferromagnet during field-cooling and realize metal-organic exchange-biased heterostructures using antiferromagnetic pinning layers.