Dr. Floriana Tuna
National UK EPR Facility, School of Chemistry and Photon Science Institute, University of Manchester, M13 9PL, U.K.
Thursday, August 30th, 11h00
Pulsed-EPR techniques have become increasingly popular in the field of molecular magnetism, being used for both characterization and manipulation of quantum states [1]. Such spin-echo methods provide a means to measure quantum coherence and entanglement in magnetic systems, as well as electron-electron and electron-nuclei interactions [2-4].
This lecture will focus on magnetic and EPR studies of d- and f-block organometallic systems. The compounds show single-ion magnet behaviour, as well as quantum coherence properties, which make them suitable as quantum memories or quantum bits (qubits). The latter are the building blocks of a quantum computer, expected to do calculations that are not possible with our conventional computers. In order to make advances in this field of research, a better understanding of the quantum coherence and its manifestation in molecular systems is necessary.
We characterise our systems through various techniques, including SQUID magnetometry and advanced EPR spectroscopy such as: HYSCORE, ENDOR, ESEEM, which allow investigating the interplay between different relaxation mechanisms in SMMs, as well as testing quantum protocols. We used CASSCF ab-initio calculations to characterise the compounds, and to guide our design of better lanthanide and actinide single-ion magnets, exhibiting larger energy barriers and/or magnetic blocking.
References
[1] S. McAdams, A. Ariciu, A. Kostopulos, J. Walsh, F. Tuna, Molecular single-ion magnets based on lanthanides and actinides: Design considerations and new advances in the context of quantum technologies, Coord. Chem. Rev. 2017, 346, 216-239.
[2] K.S. Pederson, A.M. Ariciu, et al., F. Tuna, S. Piligkos, Toward molecular 4f single-ion magnet qubits, J. Am. Chem. Soc. 2016, 138, 5801-5804.
[3] J. Ferrando-Soria, E. Moreno Pineda, et al., F. Tuna, R.E.P. Winpenny, A modular design of molecular qubits to implement universal quantum gates. Nature Commun. 2016, 25, 7:11377.
[4] A. Formanuik, A.M. Ariciu, et al., F. Tuna, E. McInnes, D. Millls, Actinide covalency measured by pulsed EPR spectroscopy, Nature Chem. 2017, 9, 578-583.
[5] M. Gregson, N.F. Chilton, et al, F. Tuna, R.E.P. Winpenny, S.T. Liddle, “A monometallic lanthanide bis(methanediide) single molecule magnet with a large energy barrier and complex spin relaxation behaviour”, Chem. Sci. 2016, 7, 155-165.
[6] R.J. Blagg, et al., F. Tuna, L.F. Chibotaru, R.E.P. Winpenny, “Magnetic relaxation pathways in lanthanide single-molecule magnets”, Nature Chemistry 2013, 5, 673-678.
[7] S.G. McAdams, E.A. Lewis, et al, P. O’Brien, F. Tuna, “Dual functionalization of liquid-exfoliated semiconducting 2H-MoS2 with lanthanide complexes bearing magnetic and luminescence proprieties”, Adv. Funct. Mater. 2017, 1703646.
[8] S. G. McAdams, D. J. Lewis, et al. P. O’Brien, F. Tuna, “ High magnetic relaxivity in a fluorescent CdSe/CdS/ZnS quantum dot functionalized with MRI contrast molecules”, Chem. Commun. 2017, 53, 10500-10503.
[9] D. M. King, N. F. Chilton, F. Tuna, et al., E. J. L. McInnes, S. T. Liddle, Molecular and electronic structure of terminal and alkali metal-capped U(V)-nitride complexes”, Nature Commun. 2016, 7, 13773.
[10] A. Ardavan, A. M. Bowen, et al., F. Tuna, R.E.P. Winpenny, ‘Engineering coherent interactions in molecular nanomagnet dimers’, NPJ: Quantum Information 2015, 1, 151012.