The two-band hybridized superconductor which the pairing occurred by conduction electron band and other-electron band are considered within a mean-field approximation. The critical temperature, zero-temperature order parameter, gap-to-Tcratio, and isotope effect coefficient are derived. We find that the hybridization coefficient shows a little effect on the superconductor that conduction electron band has the same energy as other-electron band but shows more effect on the superconductor that conduction electron band coexists with lower-energy other-electron band. The critical temperature is decreased as the hybridization coefficient increases. The higher value of hybridization coefficient, lower value of gap-to-Tcratio, and higher value of isotope effect coefficient are found.

The exact formula of Tc’s equation of two-band s-wave superconductors with Pseudogap in weak-coupling limit are derived by considering the influence of interband interaction. The pairing interaction in each band consisted of 2 parts the electron-phonon interaction and non-electron-phonon interaction are included in our model. It was found that the critical temperature is increased as Pseudogap, phonon coupling of 1st band constant and interband phonon coupling constant increased.

The specific heat jump of the two-band hybridized superconductor was studied. The two-band model is consist of conduction electron band and other-electron band with the upper and lower band of quasi-particle energy spectra occurred by hybridization. The specific heat jump was determined by making the assumption that the conduction electron band having the same energy as other-electron band, and the other-electron band having the energy near the Fermi energy. The analytic formula of specific heat jump of the two-band hybridized superconductor was derived and the effect of hybridization coefficient on the specific heat jump was investigated.

Abstract. In this research, we synthesized and investigate the physical properties of YBaCuO superconductor; Y123 and Y13-20-30. The melt process was used for heat treatment of our samples. We found that the critical temperature onset of Y13-20-33 and Y123 were at 90 K and 94 K, respectively. The morphology of Y123 superconductor has flat surface and more clear grain boundary than Y13-20-33 superconductor. However, more melted of grain boundary were found on Y13-20-33. Both samples were the orthorhombic crystal structure that c/a ratio of Y13-20-33 was higher than of Y123 superconductor.