Jing-Ci SuShih-Hung ChengWEN-JENG HSUEH2025-05-152025-05-152025-03-15https://www.scopus.com/record/display.uri?eid=2-s2.0-85219289320&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/729330The quantum tunneling effect (QTE) is a fundamental phenomenon in which particles penetrate a potential barrier despite having energy lower than the barrier height. QTE has enabled a wide range of essential applications in modern technologies. Advancements in fabrication techniques have enabled the precise growth of tunneling barriers from natural bulk materials, such as single-crystalline MgO in magnetic tunnel junctions (MTJs), which exhibit a high tunnel magnetoresistive (TMR) effect. However, MTJs with single-crystalline MgO barriers, which are essential for MRAM, face significant challenges such as limited endurance due to breakdown. Recently, artificial materials like superlattice tunneling barriers (SLTBs) have been proposed as alternative barriers to address these challenges. Nevertheless, the key conditions for forming SLTBs remain largely unexplored. In this study, we focus on establishing the criteria for forming artificial SLTBs to enable QTE. Samples are deposited using magnetron sputtering and characterized by current in-plane tunneling techniques. We demonstrate that the metal content in SLTBs must be 50 % or less for QTE to occur. Additionally, our findings indicate that the transition behavior and annealing process are independent of each other. Furthermore, the conditions established in this study extend beyond the MTJs examined here, applying to a wide range of electronic, spintronic, photonic, and superconducting devices that utilize SLTBs or alternating layers of comparable thickness. These results highlight the significant potential of devices built on SLTB technology.Magnetic tunnel junctionsQuantum transportQuantum tunnelingSpintronicsSuperlattice barrierjournal article10.1016/j.jallcom.2025.179529