We have measured magnetic penetration depthλ(0) of high-Tc YBCO samples of different density by the cavity resonant frequency shift method at 10, 16.65, and 22.3 GHz microwave frequencies. The value ofλ(0) at 10 GHz is found to decrease from 5850 Å to 2550 Å as the density of the sample increases from 4.4 to 5.3 g/cm3. The results of the frequency response of the penetration depth show a fairly constant value ofλ(0) for all the three samples in the frequency range 10–22.3 GHz. The wide variation observed in the value ofλ(0) for different density samples has been explained in terms of varying Josephson coupling strength in these ceramics.

We report results of measurement on microwave surface resistance (Rs) of YB2Cu3O7−x(YBCO) ceramic samples of different density as a function of temperature, frequency, rf and dc magnetic field.