Raman scattering in single-crystalline CuO samples has been studied. From the polarization dependence, the symmetries of the three Raman-active optical phonons have been identified. The Ag Raman mode with frequency of 290 cm ' was found to be strongly polarized along one of the crystal axes. This suggests that there are cancellations between different components of its Raman tensor.

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We have built and tested a thin-film high temperature superconducting (HTS) surface coil for MRI at 0.064T. When placed as close as possible to a conductive sample, the 6.7-cm outer diameter HTS coil had a measured signal-to-noise ratio (SNR) 1.8 times higher than a room temperature copper coil of similar size and location. Our results predict that in some cases, SNR gains of about a factor of 2 can be attained in low-field MRI systems by substituting HTS surface coils for copper coils.

We have measured the temperature-dependent electrical conductivity of Cu20 at pressures up to 500 kbar and of CuO up to 700 kbar. The high-pressure phase of Cu20 has a resistive thermal activation energy of a few meV and localization behavior below 7 K. No phase transitions were observed in CuO at pressures and temperatures up to 700 kbar and 3000 K, but its thermal activation energy decreases linearly with pressure and extrapolates to zero at about 1 Mbar.