Self-assembled structures for nanospintronic devices


Surface magnetismWe recently demonstrated that it is possible to modulate the magnetic response of a molecule via the magnetic interaction of the interface. Through a small modification we can regulate the behavior of the system. We investigated the structural orientation and the magnetic coupling of two self-assembled transition metal containing complexes. The molecules are synthesized by subcomponent self-assembly of small building blocks, display magnetic anisotropy, and can be chemically tethered onto epitaxial Fe3O4 (111). Surface anchoring induced, in the paramagnetic cobalt(II)-containing complex (CoPyipa2), a magnetic hysteresis at the Co-edge evidenced by X- ray magnetic circular dichroism (XMCD) studies. We did not observe hysteresis at the Ni-edge for the isostructural nickel(II)-containing complex (NiPyipa2). First principle ab initio calculations indicated that CoPyipa2 is ferromagnetically coupled with the surface, while NiPyipa2 undergoes an antiferromagnetic exchange coupling with weaker magnitude. These results highlight the fundamental effect that the electronic structure of a metal ion in conjunction with the nature of the organic spacer has on the resulting molecule/electrode interaction.


“Engineering the magnetic coupling at the molecule/electrode interface between self-assembled metal complexes and epitaxial ferrimagnetic iron oxide.” V. E. Campbell,* M. Tonelli, I. Cimatti, J.-B. Moussy, L. Tortech, Y. J. Dappe, E. Riviere, R. Guillot, S. Delprat, R. Mattana, P. Seneor, P. Ohresser, F. Choueikani, E. Otero, F. Koprowiak, V. Gopalan, N. Suaud, N. Guihéry, A. Galtayries, M.-A. Arrio, P. Sainctavit, and T. Mallah, Submitted, 2016.

A Phosphonate-Based Anisotropic Ni(II)-complex for Magnetic Tunnel Heterojunctions: Towards Hybrid Spintronic Devices” F. Shao, M. Tonelli, I. Cimatti, L. Tortech, R. Guillot, E. Riviere, J.-B. Moussy, L. Tortech, T. Mallah, and V. E. Campbell*, In Preparation.