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Probing the novel magnetic properties of surface trapped electrons

Objective



Research objectives and content The proposed research has grounds in the realm of materials with new magnetic properties. Stimulating magnetic properties have been observed for the so called electron rich surfaces consisting in trapped electrons at the surface of alkaline - earth oxides which are prepared either by irradiation or by metal addition to the solids. The materials obtained in so far contain trapped electrons that under certain circumstances show collective behaviour (ferromagnetic coupling with formation of quartet state centers). The research will focus on the following areas; (a) Nature of the color centres at the surface of alkaline - earth metal oxides. (The structural nature of these centres depending on the degree of surface defect and morphological regularity will be explored in depth), (b) Nature of the surface catzonie clusters; At higher concentrations of added alkali metals, a family of novel surface paramagnetic centres are formed (efforts will be focussed on methods to increase the cluster size and fully characterise the nature of these unusual surface clusters), (c) Chemical reactivity the chemical reactivity of the surface electron rich materials will be probed using a variety of organic and inorganic molecules. (d) Ferromagnetic ordering of three independent surface spins was found to produce a stable quartet state. A major object of the current research proposal will be to extend this preliminary work and to probe the magnetic properties, in particular the reversible ferromagnetic superexchange interactions of these trapped electrons using EPR and ENDOR techniques. Training content (objective, benefit and expected impact) The major aim of the project is the generation of high spin coupled systems on oxide surfaces. It is expected that longer chains of trapped electrons will be created and induced to reversibly couple ferromagnetically. This will be achieved by controlled synthesised of oxides having specific crystal planes. The expected results of the current programme will therefore be Controlled synthesis of well defined alkaline earth oxides with specific surface morphologies. Generation of surface trapped electrons by different methods. Formation of high spin surface electron rich materials. Synthesis of novel ferromagnetic materials for study of high spin systems. The benefits of the present proposal for the applicant are not limited to the opportunity of obtaining new results in an exciting and promising field of the solid state science. The training will in fact also provide an original and advanced experience in at least. two relevant areas of modem research. The applicant would first of all develop relevant skills in the preparation techniques and manipulation of advanced materials. The proposal in fact, involves 'classic' solid state syntetic methods as well as modem methods based on sol-gel chemistry or on vapour deposition. The applicant would also obtain an advanced training and skills in the field of Electron Magnetic Resonance (EMR) techniques which are of outstanding importance for the investigation of solid materials. Links with industry / industrial relevance (22)

Funding Scheme

RGI - Research grants (individual fellowships)

Coordinator

UNIVERSITY OF WALES CARDIFF
Address
Park Place, Main Building
CF10 3TB Cardiff
United Kingdom