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Functional materials studies by Mössbauer spectroscopy

<p>Mössbauer spectroscopy has been used as a powerful tool to investigate the local properties of some materials suitable as active ingredients in technological applications. </p><p>The magnetic properties of some magnetic multilayers were investigated using conversion electron Mössbauer spectroscopy. The interface quality of Fe/V(001) multilayers was determined by measuring the hyperfine magnetic field distributions. The wide distributions found were a sign of interface roughness of the order of at least 2 monolayers. Influence of the interlayer exchange coupling was also apparent. In Fe/Co(001) multilayers three different hyperfine field components belonging to interface, interface near and bulk layers could be resolved. The easy axis of magnetisation could also be deduced to be [110].</p><p>In a study of a Fe/ZnSe heterostructure, no interface diffusion could be seen for the Fe/ZnSe(001) interface. Thus enabling a high interface polarisation, which is necessary for spin polarised tunnelling. Furthermore a complicated magnetic anisotropy situation was found where the iron layers closest to the interface had magnetic moments pointing along [110] while the rest of the iron moments were aligned along [100].</p><p>Lithium ion cells with η '-Cu<sub>6</sub>Sn<sub>5</sub> and SnB<sub>2</sub>O<sub>4</sub>-glass as anodes were investigated using <sup>119</sup>Sn Mössbauer spectroscopy <i>in situ</i> during charge and discharge<i>.</i> The compounds formed after lithium-intercalation could thereby be established. In both cells the lithiation resulted in lithium alloying with tin to a maximum composition of Li<sub>4.4</sub>Sn. It had, however, different implications for the capacity of the cells.</p><p>Finally, electrochromic SnO films were investigated using <sup>119</sup>Sn Mössbauer spectroscopy. The electrochromism could be ascribed to the valence-state change from Sn(IV) to Sn(II) inside the films. </p>

Identiferoai:union.ndltd.org:UPSALLA/oai:DiVA.org:uu-1096
Date January 2001
CreatorsNordström, Erik
PublisherUppsala University, Department of Physics, Uppsala : Acta Universitatis Upsaliensis
Source SetsDiVA Archive at Upsalla University
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral thesis, comprehensive summary, text
RelationComprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X ; 630

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