Synhesis and characterization of YBa2Cu2O7±δ

Abstract

Present report summarizes the work on synthesis and characterization of one of the high temperature superconducting materials i.e. YBa2Cu3O7+δ (YBCO). The said superconducting samples were prepared by solid state reaction route. The phase purity of the prepared sample is verified using powder x-ray diffraction (XRD) measurement and found to be pure. The Meissner effect was demonstrated through an experiment using liquid nitrogen ( at T = 77K) with the pellet to reveal its diamagnetic property below its critical temperature (Tc). Resistivity-temperature (R-T) measurements have been carried out by means of an in house developed set-up. Our result revealed that even though the sample successfully demonstrates the Meissner effect but initially the temperature dependent resistivity did not show the zero resistance below Tc, this may be due to the presence of resistive in-homogeneity in the prepared sample. The further heat treatment with controlled heating and cooling rate of ~0.5 0C/min results in high quality superconducting materials as reveled from sharp drop in temperature dependent of resistivity measurements. The obtain temperature dependence of the resistivity data was investigated using polaronic and bi-polaronic models. It appears that the bipolaronic model may be more suitable for the YBa2Cu3O7+δ.