New f-Block and Mixed d,f-Block Molecular Nanomagnets

  • Eufemio Moreno Pineda

Student thesis: Phd

Abstract

"New f-Block and Mixed d,f-Block Molecular Nanomagnets" is a thesis submitted to The University of Manchester for the degree of Doctor of Philosophy in the Faculty of Engineering and Physical Sciences.Molecular Nanomagnets have been proposed as plausible candidates in a variety of futuristic applications. Thorough understanding of the magnetic properties of these systems is therefore necessary to develop devices that include such units.The aim of this thesis is to synthesise and structurally and magnetically characterise a range of systems that could be used as elementary units in three proposed applications such as: data storage devices, magnetic refrigerants and qubits for quantum computing.A series of mixed 3d/4f metal complexes were synthesised through solvothermal reactions and characterised by X-ray single crystal diffraction and SQUID magnetom- etry. Through indirect methods it was possible to obtain high magnetic entropy change for some systems. It was also possible to obtain some insight into the magnetic inter- actions within the systems through modelling the magnetic data.The role of the 4f-4f and 3d-4f interactions in two sets of molecules is also de- scribed. The first study is in an asymmetric dysprosium dimer, where through a range of experimental techniques and advanced theoretical methods, such ab-initio calcula- tions we are able to explain the role of the intramolecular interactions and their effect on the SMM properties of this system. Similarly, insight into the role of the 3d-4f interactions is achieved through the observation of the magnetic behaviour of a family of 27 tetranuclear systems, though SQUID data and ab-initio calculations.Finally, Chemical functionalization of a well-proposed qubits, namely {Cr7Ni}and subsequent reaction with a redox active metal ion, CoII/III, two {Cr7Ni} systemsare linked. The magnitude of the exchange interaction between the {Cr7Ni}-CoII-{Cr7Ni} was determined through Electron Paramagnetic Resonance. Furthermore,by chemical oxidation/reduction of the cobalt between paramagnetic and diamagneticstates, i.e. CoII and CoIII respectively, we demonstrate that the interaction can beswitched ON/OFF. This characteristic makes of these systems candidates to functionas a SWAP gate.
Date of Award1 Aug 2015
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorEric Mcinnes (Supervisor)

Keywords

  • Molecular magnetism, EPR, SQUID, quantum computing, MCE
  • Single molecule magnets, lanthanides

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