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In this work, the SmBa2Cu3Oy (Sm-123) powder was successfully prepared by solid-state reaction method under a normal air atmosphere using a stoichiometric ratio (i.e., Sm:Ba:Cu = 1:2:3) of high-purity Sm2O3, BaCO3 and CuO starting powders. Thermal properties of the as-calcined powder were studied by DSC/TGA technique and the results showed a formation of Sm-123 phase at 900 °C. The as-calcined powder was prepared by heating the starting precursors at 900 °C for 6–30 h. Phase identification was determined using an X-ray diffractometer (XRD). The quantitative phase analysis was analyzed by fitting the XRD pattern using the GSAS-II program. The result of XRD showed that the SmBa2 Cu3Oy (Sm-123) was identified as the main crystalline phase. The morphology was observed by scanning electron microscopy (SEM) with chemical composition identification from EDS mode. The surface of Sm-123 powder exhibited large agglomerates with a size range of ∼4.44–6.75 m. The Raman spectra showed a vibrational Raman-active phonon mode lying at around ∼502–508 cm–1. The peaks originated from the apical oxygen O(4) (i.e., O(4)-Ag mode) along the c-axis could be correlated with the oxygen deficiency in the CuO2 planes of orthorhombic SmBa2Cu3Oy. The calculated oxygen content from these peaks tended to decrease with increasing calcination time. All of these frequencies confirmed the presence of phonon and bonding typical for the 123-type structure.

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We have studied the effect of annealing temperature on oxygen content and thermoelectric properties of YBa2Cu3O7-x (YBCO) ceramics fabricated by hot-pressing method. The as-calcined powder was subjected to the applied pressure of 70 MPa at 800 °C for 1 h under Ar atmosphere. The YBCO ceramics were then annealed at 700 and 750 °C for 4 h in oxygen atmosphere. The XRD results showed that all samples possessed pure orthorhombic YBCO phase. The annealing process seemed to induce the reduction of the electrical conductivity and metallic-to-semiconducting transition when the annealing temperature was increased. The temperature dependence of ZT showed a close relation to that of electrical conductivity, suggesting the dominant role of the charged carriers present in these samples.