| Summary: | The (Tl0.5Pb0.5)Sr2Ca(Cu2-xCrx)O7-δ (Tl-1212) phase with x = 0 to 0.100 was prepared using the solid state reaction method. The objective of this work was to determine the optimum temperature for the formation of the Tl-1212 phase with the above composition. The samples were heated in oxygen flow with three different temperatures of 850 °C in silver foil for 5 h, and 950 °C and 1000 °C for 4 min. The materials were characterized using X-ray diffraction methods to identify phase and electrical resistance (R) measurements to the determine critical temperature. Samples heated at 950 °C showed the highest Tl-1212 phase volume fraction (94 % for x = 0). The samples heated at 1000 °C showed the highest critical temperature with x = 0.100 exhibited the highest onset critical temperature, Tc onset of 102 K. The derivative of resistance with respect to temperature (T), dR/dT of the samples heated at 1000 °C (x = 0.015 - 0.100) showed almost the same peak temperature where Tp1 = Tp2. This indicated that superconductivity for intragrain (Tp1) and between grains (Tp2) occurred at the same temperature. These results showed that 950 °C was the optimum temperature for the formation of the Tl-1212 phase and heat treatment at 1000 °C showed the highest critical temperature. © 2021 Penerbit Universiti Kebangsaan Malaysia. All rights reserved.
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