Study of production and electrical merasurement systems of high temperature superconductors

In this work, bismuth-based and Pb-dopped high Tc superconducting materials with stochiometric ratios of x=0.1, 0.2, 0.3 and 0.4 are prepared by the conventional solid-state-reaction method in four different regimes. These regimes involve combinations of once and twice calcination at 800°C with a duration of 20 hours and once and twice sintherization at 850°C with a duration of 150 hours. Sinterization was programmed to reach 850°C in 120 minutes in open air so as to cool down on its own inside the oven down to the room temperature after the sintering has finished. Pelletization was achieved by pressing the powder materials prepared under four different regimes by putting inside a mold and using an hydraulic press under a pressure of ≈450MPa at the room temperature. Eventually, effect of preperation in four different regimes, that is, effect of repetition of calcination and syntherization to the superconducting structure are studied by the XRD and SEM analyses of the obtained superconducting cuprates. Electrical measurement systems are studied in terms of resistivity-temperature measurements theoretically.