ELECTRICAL-IMPEDANCE OF SUPERCONDUCTOR POLYMER COMPOSITES

Electrical impedance measurements were carried out on high-T(c) superconducting ceramic/polymer composite materials, in which superconducting particles are embedded in a polymer matrix. The results for the impedance magnitude and phase angle versus frequency (1 kHz-1 MHz), temperature (50-290 K) and volume percentage of superconductor (0-70%) are presented. The results reveal that the a.c. electrical properties of the new composite materials go through a large change al volume percentage of powder filler around 40%, which indicates that particle-particle contacts are partially formed. Far below this composition the composite is an insulator, and above this composition the composite behaves as a semiconductor. No marked transition in impedance and phase angle was observed when the material went through the superconducting transition temperature.