Luogo: Aula Newton - Plesso Fisico
Relatore: Prof. Joris van Slageren - Institut für Physikalische Chemie, Universitat Stuttgart, Germany.
E-mail di riferimento: raffaella-burioni@fis.unipr.it
Abstract:
Molecular nanomagnets (MNMs) are coordination complexes consisting of one
of more transition metal and/or f-element ions bridged and surrounded by organic
ligands. Some of these can be magnetized in a magnetic field, and remain magnetized
after the field is switched off.
Because of this, MNMs have been proposed for magnetic data storage
applications, where up to 1000 times higher data densities than currently possible can be
obtained. Other MNMs were shown to display quantum coherence, and, as a
consequence, are suitable as quantum bits.
Quantum bits are the building blocks of a quantum computer, which will beable to
carry out calculations that will never be possible with a conventional
computer. The magnetic bistability of MNMs originates from the magnetic anisotropy of
the magnetic ions, which creates an energy barrier between up and down orientations of the
magnetic moment.
Currently, most work in the area focuses on complexes of either lanthanide
ions or low-coordinate transition metal ions. Synthetic chemical efforts have led
to a large number of novel materials, but the rate of improvement has been slow.
Therefore a better understanding of the origin of the magnetic anisotropy is clearly
necessary.
To this end we have applied a wide range of advanced spectroscopic
techniques, ranging from different electron spin resonance techniques at frequencies
up to the terahertz domain to optical techniques, including luminescence and
magnetic circular dichroism spectroscopy. We will discuss two examples, one from the area of
lanthanide MNMs [1], one a transition metal MNM [2].
[1] Y. Rechkemmer, J. E. Fischer, R. Marx, M. Dörfel, P. Neugebauer, S.
Horvath, M. Gysler, T. Brock-Nannestad, W. Frey, M. F. Reid, J. van
Slageren, J. Am. Chem. Soc. 2015, 137, 13114.
[2] Y. Rechkemmer F.D. Breitgoff, M. van der Meer, M. Atanasov, M. Hakl, M.
Orlita, P. Neugebauer, F. Neese, B. Sarkar, J. van Slageren, Nat. Commun.,
2016, accepted, DOI: 10.1038/ncomms10467