Inter-granular effects at high magnetic fields of cuprate and iron chalcogenide superconducting materials

The weak links effects are one of the main challenges for effective power applications of high temperature superconducting materials. Studies of these effects help for their better understanding and subsequent improvement. An overview analysis of the intergranular properties of cuprate (Y0.8Ca0.2Ba2Cu3O7-delta) and iron-based chalcogenide (FeSe0.5Te0.5) polycrystalline samples was carried out, by means of series of electro-transport experiments at different magnetic fields. The temperature evolution of the Josephson coupling and intrinsic superconductivity effects for the both systems was constructed. The FeSe0.5Te0.5 compound shows very stable and superior behavior compared to Y0.8Ca0.2BCO up to the highest magnetic fields (14T) used. We have explored FeSe0.5Te0.5 Josephson weak links influence (as a non-linear process) over the resistive transition using different AC current amplitudes and applying the sensitive AC transport third harmonics technique.