화학공학소재연구정보센터
Journal of the American Ceramic Society, Vol.102, No.10, 5705-5715, 2019
Interface reaction-governed heteroepitaxial growth of YBa2Cu3O7-delta film on CeO2-buffered technical substrate
Due to the high growth rate and environmental-friendly, fluorine-free metal-organic decomposition routes (FF-MOD) have attracted more attention for growth of high-quality YBa2Cu3O7-delta (YBCO) films. Few works have been performed when using technical substrates. In this study, correlation among the sintering process, microstructure, and superconductivity of the YBCO was systematically established on the technical substrates capped with CeO2 layer. We found that the optimal process conditions are mainly related to the enhanced transient liquid phase and BaCeO3. Combined X-ray diffraction and scanning electron microscopy analyses indicate that high-quality growth of YBCO film is a trade-off of two different competition phenomena during sintering: (a) the presence of enhanced transient liquid phase, (b) the formation of BaCeO3 at the interface. The former is beneficial to YBCO epitaxial growth/structure rearrangement, while the latter should be suppressed in view of minimizing YBCO partial decomposition triggered by the interfacial reaction. Moreover, we confirmed that both two aforementioned phenomena are somehow associated with the cross-linkage between the sintering temperature and pO(2) during the YBCO conversion. According to this systemic study, the key parameters are defined to avoid the BaCeO3 formation prior to the YBCO orientation nucleation. Structure and superconductivity of the YBCO film were also investigated. Remarkably, a high J(c) value of 3.69 mA/cm(2) (77 K, sf) was obtained in the YBCO film grown on the CeO2 technical substrate deposited under optimized deposition conditions, which is rather comparable with that on the LaAlO3 single crystal. TEM cross-sectional observation reveals that the enhanced J(c) (B) properties of the YBCO film are mainly contributed by high density of short stacking faults. This work demonstrates the feasibility of FF-MOD to fabricate high-performance YBCO films on the CeO2-buffered technical substrate.