9623858 Imai The mechanism of high temperature superconductivity in doped copper oxides is still highly controversial. The fundamental difficulty lies in the fact that strong carrier-carrier correlation effects do not allow us to describe the normal metallic state above Tc based on the conventional wisdom. Moreover, the magnetism and statistical properties of the undoped parent antiferro- magnetic insulators are hard to understand. Recently, a new NMR (Nuclear Magnetic Resonance) spectrometer has been designed and developed at the Center for Materials Science and Engineering at M.I.T. The spectrometer is ideally suited to investigate carrier- carrier correlation effects, metal-insulator transitions, magnetic and statistical properties of quasi 2d quantum spin systems, the symmetry of the superconducting order parameter, and related phenomena. In the proposed project, a variety of high Tc copper oxide superconductors and related materials will be studied using the spectrometer with particular emphasis on NMR experiments at elevated temperatures. %%% The nuclear magnetic resonance technique is an ideal microscopic, nondestructive probe into the physical and chemical properties of solids. Recently, a new NMR spectrometer has been developed at the Center for Materials Science and Engineering at M.I.T. The spectrometer allows one to conduct unique experiments to investigate high temperature superconductors and related materials. Most notably, difficult experiments at elevated temperatures can be conducted in a routine manner. In the proposed project, the NMR spectrometer will be utilized to understand the mechanism of high temperature superconductivity and related phenomena in copper oxide superconductors. ***
