Surface engineering of the flexible metallic substrate by SDP‐Gd‐Zr‐O layer for IBAD‐MgO templates

Abstract

AbstractTuning substrate properties is an effective methodology to modulate the texture development of MgO films deposited by ion beam‐assisted deposition (IBAD) process for epitaxial oxide films. Herein, a solution deposition planarization (SDP) technique is employed to deposit Gd‐Zr‐O layer for engineering surface properties of the flexible metal substrate. The correlation between the Gd‐Zr‐O thin film microstructure and the IBAD‐MgO texture is investigated. The coordinated study on atomic force microscopy (AFM) and reflection high‐energy electron diffraction (RHEED) reveal that the grain coarsening during high‐temperature sintering negatively influences the texture formation of IBAD‐MgO. Moreover, the chemical environment of the atoms on the surface of Gd‐Zr‐O seed layer also plays a critical role, which is normally overlooked. The X‐ray photoelectron spectroscopy (XPS) analysis indicates that the carbon residue and intermediate phase result in the poor texture of the IBAD‐MgO. This phenomenon is related to the partial decomposition and synthesis reactions due to the lower sintering temperature or reduced surface to volume ratio. We demonstrate the high‐quality texture of IBAD‐MgO layer, deposited on mono‐coated thick Gd‐Zr‐O film, by using optimal heat‐treatment conditions. The cross‐sectional TEM images present the dense Gd‐Zr‐O film with Gd2Zr2O7 nanograins. The multifunctionalities, such as planarization, a barrier layer, and seed layer, of Gd‐Zr‐O layers are realized in full‐stacked CeO2/LaMnO3/IBAD‐MgO/SDP‐Gd‐Zr‐O/C276 samples. This work demonstrates a route for simplifying the architecture of 2G‐HTS using Gd‐Zr‐O layer and explores the effect of the surface properties on texture formation in IBAD‐MgO layer.