Superconducting properties and hardness of DyBa2Cu3O7-δ-Ag composite

Ag has been useful in fabricating high temperature superconducting wires and tapes. It has also been used to improve the physical properties of the materials. This paper reports on the effects of Ag addition on the physical properties of high temperature DyBa2Cu3O7-δ superconductor (Tc zero ∼ 90 K). A series of the DyBa2Cu3O7-δ - Agx composite was prepared with varying amount of metallic silver (x = 0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0). The samples were prepared by the standard solid state reaction method which consists of 48 hours of calcination followed by 24 hours of sintering at 905 oC. Resistance measurement to determine the critical temperature (Tc) of the composites was done using the four-point probe method. The 123 structure and presence of silver was confirmed by powder X-ray diffraction and Energy Dispersive X-ray Analysis (EDAX) respectively after which the theoretical densities and porosities of the samples were calculated. The paper also reports results of Vickers Microhardness measurements and their variation with the different amounts of silver in the composites. (Author)