Processing and grain boundary effects in Nd1-xBa2-xCu3O7+d superconductors

This paper reports on the Nd1-xBa2-xCu3O7+d system shown by a number of investigators to exhibit a solid solution for x = 0 to x = 0.5 for temperatures above the orthorhombic to tetragonal transition of the x = 0 end point. Published measurements of the superconducting properties as a function of x have not yielded a consistent behavior of transition temperature upon composition. While x-ray diffraction and TGA measurements are generally performed on powdered samples, superconductivity measurements are performed on sintered compacts. D.C. Magnetization measurements of sintered compacts have shown that the transition width and superconducting fraction is strongly dependent on the temperature at which the material is sintered