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A pulsed field gradient spin echo NMR spectrometer has been assembled by interfacing a programmable pulse generator and a data acquisition system designed and fabricated in our laboratory with other imported units. Calibration results of the magnetic field gradients are presented.

Oxides with different cation ratios 2122, 2212, 2213 and 2223 in the Ti-Ca-Ba-Cu-O system exhibit onset of superconductivity in the 110–125 K range with zero-resistance in the 95–105 K range. Electron microscopic studies show dislocations, layered morphology and other interesting features. These oxides absorb electromagnetic radiation (9.11 GHz) in the superconducting phase.

The critical current densities (Jc) have been measured at 77K in high pressure oxygen sputtered thin films of YBa2Cu3O7−xsuperconductor using the non-resonant rf absorption technique. High values ofJc(∼ 105A/cm2) are observed in these relatively large area (∼ 1·2 cm2) films.

Besides ag≈ 2 signal which disappears on cooling to the superconductingTc, YBa2Cu3O7and related oxides show a near-zero-field signal in the superconducting state with certain unusual features attributable to a “superconducting glassy state”.