In-plane orientation effect on the melting behaviour of YBCO thin film.

By means of high-temperature optical microscopy (HTOM), a 60 °C gap in initial melting temperature between two YBa2Cu3O(x) (Y123) thin films was found in situ. Using these two films as seeds, liquid phase epitaxy (LPE) dipping experiments showed the same tendency in the melting behaviour. The in-plane orientation was detected by x-ray diffraction (XRD) pole figure. On the basis of results from HTOM, LPE and XRD, it was unveiled that the interface structure has a predominant influence on the melting mode. A semi-coherent interface suppresses not only the melting growth but also the melting nucleation, while an incoherent interface encourages both of them. (In this work, melting of YBCO refers to the peritectic decomposition of Y123.).