Abstract
The coexistence of structural polarity and magnetism within a single material can give rise to coupled electromagnetic states, such as those observed in multiferroics. Unlike widely studied insulating polar materials, polar magnetic metals host unique coupling among their symmetry-breaking lattice distortions, spin order and intrinsic conductivity, offering a unique platform for emergent magnetotransport phenomena. Here we report a polar antiferromagnetic metallic state in the double-layered Ruddlesden–Popper perovskite Sr3Co2O7. The cobalt ions at different sublayers develop inequivalent ionic displacements, geometrically generating a polar state while preserving metallic conductivity. Furthermore, the quasi-two-dimensional crystalline architecture hosts an A-type antiferromagnetic order with the Néel vector along the c axis, stabilized by interlayer hybridization of Co-d orbitals. Strikingly, despite negligible remanent magnetization, we observe a notable zero-field anomalous Hall conductivity, ascribed to the coupling between antiferromagnetism and polarity. This work highlights the pivotal role of symmetry engineering and geometric distortion in layered perovskites for designing multifunctional quantum materials.
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All data needed to evaluate the conclusions are available in the Article and/or its Supplementary Information. Additional data related to this Article may be requested from the corresponding authors. Source data are provided with this paper.
Change history
15 January 2026
In the version of this article initially published, grants listed in the Acknowledgements were incomplete and have now been amended to read "H.C. acknowledges the National Natural Science Foundation of China under project numbers 12374064 and 12434002" in the HTML and PDF versions of the article.
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Acknowledgements
This study was financially supported by the National Key R&D Program of China (grant number 2023YFA1406400), the National Natural Science Foundation of China (grant numbers 52025024, 52388201 and 12421004) and the China Postdoctoral Science Foundation (grant numbers 2022M721769 and 2022M711870). H.C. acknowledges the National Natural Science Foundation of China under project numbers 12374064 and 12434002, Science and Technology Commission of Shanghai Municipality under grant number 23ZR1445400 and a grant from the New York University Research Catalyst Prize. L. Y. acknowledges the support from the National Natural Science Foundation of China (grant numbers 12361141826 and 12074212), and the Beijing Natural Science Foundation (grant number Z240006). X.S. acknowledges support from International Postdoctoral Exchange Fellowship Program of China (Talent-Introduction Program). X.S. and Ya.Z. acknowledge the Shuimu Tsinghua Scholar Program of Tsinghua University.
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P.Y. conceived the study. Yu.Z. synthesized the Sr3Co2O7 materials with assistance from Y.W. and K.X. X.S. and Yu.Z. performed the XRD measurements with assistance from C.L. and J.Zh. Yu.Z. and X.S. designed and fabricated the devices with the assistance of S.S. Yu.Z. carried out the magnetic measurements. X.S. performed the transport measurements. Ya.Z. performed the STEM measurements. Z.L. and H.C. carried out the first-principles calculations. Y.L., S.W., C.L. and Q.H. performed the XAS measurements. L.L. performed SHG measurements under the supervision of L.Y. J.Za., T.N., D.Y., G.Z. and S.Z. provided scientific insights. X.S., Yu.Z., H.C. and P.Y. wrote the paper, and all authors discussed the results and commented on the paper.
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Supplementary Notes 1–5, Figs. 1–13, Table 1 and References 59–71.
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Structural and magnetic properties of Sr3Co2O7 at various structures. l represents the lattice constants (a, b, c). m represents the Co magnetic moment. Δ represents the magnitude of Co cation displacements, which is along the c axis for the OOP cases and within the ab plane for the IP cases. E − EC represents the energy difference between a crystal structure and the centrosymmetric crystal structure.
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Zhou, Y., Shu, X., Zhang, Y. et al. Geometry-driven polar antiferromagnetic metallicity in a double-layered perovskite cobaltate. Nat. Mater. 25, 231–237 (2026). https://doi.org/10.1038/s41563-025-02392-7
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DOI: https://doi.org/10.1038/s41563-025-02392-7
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