Exploring Structural Features and Growth Mechanisms in GdBa₂Cu₃O_7- /LaFeO₃ Bilayers on SrTiO₃ Substrates

This study investigated a novel approach to enhance the performance of superconductors by applying a LaFeO₃ (LFO) buffer layer on a GdBa₂Cu₃O_7- (GdBCO) superconducting thin film. LFO is a rare-earth orthoferrite (REFO) materials. The objective was to assess how the thickness of the LFO layer influences the superconducting properties of the GdBCO material. LFO layers were fabricated at thicknesses of 50, 100, 150, and 200 nm, and subsequently, a 200 nm thick layer of GdBCO was deposited to create a bilayer structure. This study represents the first utilization of a REFO material, specifically LFO, as a buffer layer, with findings showing its growth in a pseudocubic structure. We thoroughly examined the characteristics of LFO, including its structural, surface, and strain states, focusing on the impact of varying layer thicknesses. Additionally, we investigated changes within the GdBCO/LFO bilayer and analyzed how LFO influences the properties of GdBCO. It was found that the application of the LFO buffer layer by varying thicknesses not only provided structural compatibility with GdBCO but also consistently resulted in the improvement of its superconducting transition temperature, as evidenced by the enhanced Tc-onset values reaching up to 92.4 K with an LFO thickness of 150 nm. These findings reveal significant potential in utilizing REFO materials, particularly those derived from LFO, as effective buffer layers in superconductor applications.