True Material Selection in a Liquid Phase Epitaxy System for Growth of High-Tc Superconducting Films

The chemical stability of liquid-phase epitaxy (LPE) materials plays a decisive role in the quality of high-temperature Bi2Sr2Can-1CunO2n+4+δ (BSCCO) superconducting films. In this study, the corrosion and dissolution behavior of two commonly used crucibles (made of Pt, and Pt-Rh alloy) and two substrates (MgO and NdGaO3) in BSCCO/KCl solution were systematically investigated during the growth of Bi2Sr2CaCu2O8+δ (Bi-2212) films. Corrosion effects observed by optical and SEM imaging on the Pt–Rh crucible and NdGaO₃ substrate led to a detailed investigation of impurity incorporation into the films. The presence and origin of these impurities were identified by SEM-EDS, while their influence on the crystal structure and superconducting properties was evaluated using XRD and SQUID magnetometry, respectively. Imaging and elemental analysis show that films incorporating impurity atoms from the substrate exhibit degraded texture, correlated with the solubility of the surface material. This degradation is further accompanied by a marked suppression of superconductivity, arising from the combined effects of extrinsic impurities and the compromised microstructure. Overall, the findings underscore the critical importance of LPE material’s inertness in controlling impurity incorporation and preserving both the textural integrity and superconducting behavior of LPE-grown Bi-2212 films. This work provides essential insights into impurity–flux interactions and highlights pathways to improve the reproducibility and quality of epitaxial Bi-2212 film growth.