Metallurgy and critical currents in YBa 2Cu 3O 7 wires

Abstract

A development of powdermetallurgical processed YBa 2Cu 3O 7 wires with transport critical current densities exceeding 10 3 A/cm 2 at 77 K is presented. Attempts to induce texturing in YBa 2Cu 3O 7 wires and their consequence on J c are described. The complete characterization of the metallurgical state includes X ray diffraction measurements and Auger analysis as well as density and resistivity measurements on the core material. The main factor limiting the critical current densities in YBa 2Cu 3O 7 wires resides in the weak links between the grains. By means of inductive measurements on the superconductor (without the matrix), the respective inter- and intragrain critical current densities were separated. This possibility of a direct observation of the intergrain currents allows to follow more closely further progresses in this field. Critical current measurements on wires with and without the matrix are presented.