The use of magnetic molecules and the thermal stabilization of their magnetic state is mandatory in the field of molecular spintronics and information technology. We here propose a route to grow a well-ordered spin network with tunable magnetic properties and a magnetic activity at device working conditions by exploiting self-assembly of metal phthalocyanine molecules on a functionalised Gr sheet. Our preliminary results show that we are able to switch the magnetic coupling from anti-ferromagnetic (AFM) to ferromagnetic (FM) for different occupation and symmetry of the magnetically active molecular orbitals. In this project, we plan a thorough investigation of the proposed system and to unveil the driving forces of the magnetic coupling, in order to clarify the fundamental interaction mechanism and identify the optimal magnetic configuration. The subtle interplay between ordering, molecular adsorption sites, and electronic interaction will be addressed together with their influence on the magnetic state of the spin network by means of complementary experimental techniques.
Metal network architectures at the nano-scale have potential impact on several applications, in particular magnetic molecules, regularly arranged in networks, can be used for spintronic applications. Their magnetization can be thermally stabilized by adsorbate-substrate magnetic interactions, and the electronic decoupling from the substrate can preserve the magnetic moment.
The research in this field is strongly pushing forward a controlled route to design well-ordered spin networks, with tunable properties, to be exploited in spintronics devices. We found that by exploiting the presence of inequivalent adsorption sites on a functionalized Gr sheet a well-ordered molecular network can be obtained, with tunable molecule-substrate interaction. We have partially demonstrated, and aim to confirm, that the occupation and symmetry of the magnetically active orbitals play a fundamental role in determining the coupling path (direct or indirect) and, accordingly, allow for a fine tuning of the sample magnetic activity.
Very little experimental investigation on superexchange interaction can be found in the literature and, in particular, on the role of the non-magnetic mediators and the overlap between their orbitals and the metal-related ones. Moreover, the optimized system will match the characteristics required from a model system to be exploited in technological devices, with a magnetic state, preserved by the presence of the Gr sheet, stable at device working conditions.
The expected results, beyond their interest for the advancement of basic scientific knowledge, have potential applications and represent technological advances for the future of nanoelectronics and spintronics. In particular, the activity of the project can deepen the understanding of these issues:
(i) tailoring graphene and 2D material functionalities by establishing interfaces with metals;
(ii) the molecular-level understanding of the electronic and magnetic properties of SMMs
(iii) self-assembling of molecular architectures for miniaturized data-storage applications (stable nanomagnets with controlled magnetic anisotropy).
Furthermore nanomagnets of decreasing size and organized into regular patterns offer new perspectives for extrapolating established principles of magnetic storage into the future developments of nanoelectronics and spintronics. In the last fifty years, it has been proven that magnetism offers the most successful means of storing information in a two-state configuration (parallel or antiparallel associated with bit 0 and 1). To go one step further, from classical to quantum magnets, it is widely agreed that nanomagnets have a great potential as functional qubits for quantum computation. If they can be made extremely small, and almost identical, it will be possible to attain significant statistical averages over a small number of particles, approaching the Terabit/inch^2 limit.
This proof-of-concept production of ordered metal arrays on graphene can open wide perspectives towards innovative industrial applications. In particular, the development of graphene-based devices would contribute to the establishment of "carbon based electronics", that would have a much lower environmental impact than current silicon-based electronics and would not suffer from the lack of raw material typical of many current technologies.