Manipulation of Magnetism and Hall Effects in Oxide Superlattices by Dimensionality Crossover and Interfacial Dzyaloshinskii-Moriya Interaction

Dimensionality crossover can bring about distinct functionalities in solid materials. Here, the manipulation of magnetism and Hall effects in atomic-scale oxide superlattices of SrRuO₃/LaFeO₃ by harnessing the dimensionality effect in conjunction with the interfacial Dzyaloshinskii-Moriya interaction is demonstrated. As the electronic system approaches the thickness-driven magnetic transition and the concurrent metal-to-insulator transition, the drastic change in electronic band structure induces an unexpected sign reversal of the ordinary Hall coefficient at low temperature along with a distinct temperature dependence of the anomalous Hall resistivity. This carrier-type inversion can also be controlled by fine tuning of the interlayer exchange interaction between neighboring SrRuO₃ layers, attesting to the crucial role of dimensionality. Moreover, topological Hall effects have been uncovered for a narrow thickness window of SrRuO₃, which is attributed to the inherent Dzyaloshinskii-Moriya interaction at the G-type antiferromagnetic/ferromagnetic interface with minimal structural modification. Such topological Hall effect vanishes as the LaFeO₃ layer is thinned to a single monolayer, confirming its intimate correlation with the antiferromagnetism of LaFeO₃. Our results illustrate the effective control of magnetic and electronic properties in artificial oxide crystals via atomically precise synthesis.