Mercoledì 9 Marzo 2016 - Ore 16:30 - Seminario di Dipartimento - Joris van Slageren - Spectroscopic Investigation of the Origin of Magnetic Bistability in Molecular Nanomagnets

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