Preparation of Nd1.85Ce0.15CuO4 superconducting thin film by pulsed laser deposition

In this study, the epitaxial growth process of negative-type high-temperature superconducting thin film Nd1.85Ce0.15CuO4 (NCCO) by pulsed laser deposition is reported. First, the relationships between the heat treatment temperature of NCCO films, target-substrate distance, and oxygen pressure and the phase formation of a superconducting (00l)-T′ phase were investigated. It was found that a good superconducting (00l)-T′ phase could be epitaxially prepared from NCCO films only when the heat treatment temperature was higher than 650 °C. However, when the heat treatment temperature increased to 820 °C, NCCO films underwent thermal decomposition. The optimal oxygen pressure of phase formation for NCCO films, corresponding to the heat treatment temperature range of 650–800 °C, was given. Furthermore, the effect of deoxidization temperature on the superconductivity of NCCO films was also studied. The superconductivity of NCCO films was obtained only when the heat treatment temperature reaches 770 °C and the deoxidization temperature reaches 750 °C. The NCCO films obtained at 800 °C heat treatment temperature and 750 °C deoxidization temperature showed the best superconducting properties, and the initial superconducting transition temperature was as high as ∼30 K, with a transition width of only ∼0.15 K.