Funding and institutional support came from JSPS-KAKENHI (Grant 20H02704), with facilities at SPring-8, KEK-PF, and the Institute for Materials Research at Tohoku University involved under their program approvals.

A Tokyo Metropolitan University team developed atomically layered Sr3Cr2O7−δ thin films that exhibit a five-order-of-magnitude resistivity drop upon oxidation, far exceeding reductions in non-layered counterparts like SrCrO3.

The findings propose a design principle: pairing oxidation with a layered atomic structure can be extended to a broader class of films, potentially advancing memristor technology and energy-efficient AI hardware.

A new study shows that resistivity changes in atomically layered Sr3Cr2O7−δ thin films arise from a synergy between oxygen incorporation (oxidation state changes in chromium) and structural modifications in the layered film, enabling much easier electron conduction.

Comparative analysis indicates the layered structure amplifies the resistivity drop upon oxidation, with coordinated structural and electronic changes jointly enhancing conductivity.

The work was published in Chemistry of Materials under the title Oxidation-Induced Giant Resistivity Change Associated with Structural and Electronic Reconstruction in Layered Sr3Cr2O7−δ Epitaxial Thin Films, with late-September 2025 dating and acknowledgment of JSPS-KAKENHI and the involved facilities.

The same team highlighted that the oxide’s layered structure enables this dramatic conduction pathway, reinforcing the advantage of the layered approach over three-dimensional materials.

Using pulsed laser deposition, researchers produced high-quality epitaxial layered films and found that air annealing introduces oxygen, reorganizing the structure and chromium oxidation state to dramatically improve conductivity.

The study emphasizes that heating in air drives oxygen incorporation and structural/electronic reconstruction, leading to the dramatic electronic changes observed.

Overall, the results suggest broader applicability: other layered oxide films could be engineered for similarly large resistivity modulations, signaling potential advances in next-generation electronics.

Key methods include growing Sr3Cr2O7−δ films via pulsed laser deposition and annealing in air to drive oxygen incorporation and chromium oxidation state changes, paired with structural analyses linked to transport properties.

Moreover, the study points to the material system’s promise for enabling energy-efficient next-generation devices, including memory elements for AI computing, and suggests research directions across similar layered oxides.

This work positions oxidation and layered architecture as a new paradigm for future memristors and computing devices, with potential implications for AI hardware development.

Detailed structural work shows the layered architecture magnifies the role of oxygen vacancies and their filling during annealing, creating a unique conduction pathway not present in three-dimensional materials.