Oxygen-17 NMR Relaxation Studies of Oxide Superconductors PDF Download

Author: Linda Reven
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Languages : en
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Book Description
In this study, solid state nuclear magnetic resonance (NMR) spectroscopy is used to investigate the structural, electronic, and dynamical properties of a variety of high temperature oxide superconductors and metal carbonyls adsorbed on metal oxide surfaces. The first five chapters describe the $\sp{17}$O Knight shift, nuclear spin lattice and spin-spin relaxation measurements carried out on a large number of cuprate, bismuthate and plumbate superconductors. After briefly reviewing the basic theory of the NMR parameters of metals in the normal and superconducting states, a detailed $\sp{17}$O NMR study of YBa$\sb2$Cu$\sb3$O$\sb{\rm 7-x}$, is described in Chapter 2. Chapter 3 contains a comparative study of Tl$\sb2$Ba$\sb2$CaCu$\sb2$O$\sb{\rm 8+x}$, Bi$\sb2$Sr$\sb2$CaCu$\sb2$O$\sb{\rm 8+x}$, YBa$\sb2$Cu$\sb3$O$\sb{\rm 7-x}$, and La$\sb{1.85}$Sr$\sb{0.15}$CuO$\sb4$. In this chapter, the $\sp{17}$O nuclear spin lattice relaxation and Knight shift measurements on La$\sb{1.85}$Sr$\sb{0.15}$CuO$\sb4$ are compared to the theoretical model of Monien, Millis, and Pines of an antiferromagnetic Fermi liquid state. In Chapter 4, it is shown that the normal state nuclear spin lattice relaxation behavior of the "copper-free" superconductors can be accounted for by a simple p conduction band model. The $\sp{17}$O NMR results for the different families of oxide superconductors are summarized in Chapter 5. The $\sp{17}$O NMR parameters of the bismuthate and plumbate superconductors show these materials to be weakly metallic oxides with T$\sb1$T values which are consistent with a BCS-like relationship between the electronic density of states and T$\sb{\rm c}$. The normal state of the cuprate superconductors display properties consistent with the presence of magnetic interactions and their T$\sb1$T values show little variation with T$\sb{\rm c}$. Finally, in Chapter 6 of this thesis, earlier work using $\sp{13}$C variable temperature magic angle sample spinning (MAS) NMR to study the surface chemistry and fluxional behavior of Fe$\sb3$(CO)$\sb{12}$ and Ru$\sb3$(CO)$\sb{12}$ adsorbed on a variety of metal oxide surfaces is described.