30.11.2016

Prof. Dr. Joris van Slageren (Institut für Physikalische Chemie University
Stuttgart):
Molecular Nanomagnets for Data Storage and Quantum Computing


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. 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. 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 be able to carry 
out calculations that will never be possible with a conventional computer.
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.

In addition, we have strived to elucidate the origin of the long-lived 
quantum coherence and the decoherence mechanisms. We have shown that a 
quantitative simulation of the coherence decay is possible.