HIGH PULSED CURRENT AND VOLTAGE MEASUREMENTS ON SINTERED BIPBSRCACUO CERAMICS SUPERCONDUCTORS

High pulsed currents attaining 3300 A with a duration varying from 1.2 5 to 20 milliseconds have been applied at 77 K to sintered Bi1.8Pb0.4S r2Ca2.2Cu3O10.3+x long bars. Measurements of voltage versus applied cu rrent determine the critical current Ic = 60 A, and the conditions for superconductivity recovery. Two types of behaviour are observed : (i) When the mean temperature T raises up to T < 95 K a critical current is recovered at the end of the pulse. (ii) When the temperature goes b eyond 95 K, Ic goes to zero after the pulse. The temperature increases up to 43 K for a 20 ms pulse. No deterioration in the sample is obser ved and experiments can be reproducibly repeated. Voltages as high as 90 V have been measured, corresponding to an electrical field of 1100 V/m. The maximum instantaneous power applied to the material is 180 GW /m(3) and the maximum energy per unit volume transmitted to the sample after a 20 ms pulse is 75 MJ/m(3).