Authors:

Wenchi Liu

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About Paper:

Precise control of oxygen stoichiometry is critical for stabilizing functional oxide thin films, as oxygen content strongly influences crystalline ordering, transport behavior, and phase stability. Conventional annealing studies often rely on ex-situ measurements, limiting insight into real-time property evolution during thermal processing. This work centers on the development of a versatile in-situ resistivity measurement and real-time data visualization platform designed to directly monitor thin film oxides during annealing. Controlled post-growth annealing is essential for stabilizing functional oxides, as oxygen stoichiometry strongly influences crystalline ordering and electronic properties. Uncontrolled annealing can lead to unwanted phase evolution and degradation, motivating real-time probes during thermal treatment. We report the development of an in-situ resistivity measurement and real-time plotting system integrated into a tube furnace, designed to operate at temperatures up to 400 °C under a variety of gas environments, including ozone. By monitoring resistivity during annealing, this approach enables identification of optimal processing conditions, provides insight into oxygen-driven phase transitions, and facilitates on-the-fly materials-by-design. Preliminary measurements on thin film transition metal oxides demonstrate reproducible resistivity evolution during thermal cycling. In addition, the effectiveness of capping layers in mitigating oxygen-loss-induced degradation is investigated, highlighting their role in controlling soft-chemistry-driven phase evolution. In the practice of investigating specific materials systems, the platform was applied to SrFeO; thin films capped with 4-unit-cells of SrTiO;, which were stable up to 100 °C. The system has also been employed for precision annealing studies of La3Ni,O, in pursuit of stabilizing its superconducting phase. While superconductivity has not yet been achieved, the platform enables controlled thermal tuning and continuous feedback during phase optimization. Importantly, the architecture is material-agnostic and extendable to diverse thin film 'systems requiring controlled annealing environments. This work establishes a broadly applicable in-situ characterization framework for advancing oxide electronics and emergent quantum materials.

Source:

Northwestern University

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Co-authors:

Wenchi Liu