Fabrication and characterization of superconducting BiPb2223 tapes in new configurations for AC losses reduction

From 1986 the investigations done in superconductivity have given an amazing progression. New superconductors in the copper oxide families have been found with much higher running temperatures than the previous known materials. These new superconductors have similar properties but very useful differences. The most promising superconducting material for electrical transport are composites of (Bi,Pb)2Sr2Ca2Cu3O10 or BiPb-2223, (Bi,Pb)2Sr2Ca1Cu1O8 and YBa2Cu3O7. The higher temperature obtained in the new type of superconductor puts at hands new applications as for example current cables. Nowadays, copper wires are used for the transport of electrical energy from the sources of generation to the points of consumption. Copper, even being a good metallic conductor and cheap material, has losses in electric transport. In some cases, superconducting materials can replace its use where the size and the amount of energy are critical. Electrical energy is generally distributed by Alternating Currents (AC) that generate losses in the material that should be minimized. AC losses in superconductors come from the protective metallic sheath currents and from the hysteretic losses of superconductors. These losses can be reduced by an optimum selection of barrier materials and configurations. The purpose of this thesis is the study of superconducting tapes characteristics and the development of new tapes for the reduction of AC losses.