TEMPERATURE-DEPENDENCE OF THE NQR FREQUENCY AND LINEWIDTH OF THE HIGH-TC SUPERCONDUCTOR YBA2CU3O7-DELTA

For YBa2Cu3O7−δ powder samples of different average grain sizes the temperature dependences of 63Cu NQR frequencies and signal intensities are reported for the Cu(1) site in a temperature range of 4–300 K. Both quantities show a non-monotonic behaviour in the vicinity of the superconduction transition temperature Tc. In the superconducting state the line shape of the NQR signal in zero-field depends on the strength of the dc magnetic field applied during the cooling-procedure. The resulting linewidth yields information about the internal trapped magnetic field. © 1990, Verlag der Zeitschrift für Naturforschung. All rights reserved.