Strain-tunable magnetism at oxide domain walls

Abstract

Applying stress to a ferroelastic material results in a nonlinear strain response as domains of different orientations mechanically switch. The ability to write, erase and move domain walls between such ferroelastic domains suggests a method for making nanoelectronics where the domain wall is the device. However, little is known about the magnetic properties of such domain walls. A fascinating model system is SrTiO3, where the ferroelastic domain walls display strain-tunable polarity and enhanced conductivity. Here, we reveal a long-range magnetic order with modulations along the ferroelastic domain walls in SrTiO3 and SrTiO3-based heterointerfaces, which manifests itself as a striped pattern in scanning superconducting quantum interference device maps of the magnetic landscape. In conducting interfaces, the magnetism is coupled to itinerant electrons with clear signatures in magnetotransport measurements. The magnetic state is also coupled dynamically to the lattice and can be reversibly tuned by applying local external forces. This study raises the possibility of designing nanoscale devices based on domain walls where strain-tunable ferroelectric, ferroelastic and ferromagnetic orders may coexist.

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Fig. 1: Scanning SQUID maps of striped magnetic order.
Fig. 2: Anomalous Hall effect.
Fig. 3: Pressure-dependent magnetic signal.
Fig. 4: Coupling between lattice, spin and charge.

Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding authors upon reasonable request.

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Acknowledgements

We acknowledge useful discussions with R. Claessen and P. Schütz from the University of Würzburg, J. Levy from Pittsburgh University and Y. Zhang and Y. Gan from the Technical University of Denmark. In addition, we thank C. Bernhard and M. Yazdi for insight into the temperature dependence of the carrier density extracted by infrared ellipsometry. D.V.C. and N.P. were supported by the NICE project, which has received funding from the Independent Research Fund Denmark, grant no. 6111-00145B. L.K. acknowledges support by the Israel Science Foundation founded by the Israel Academy of Sciences and Humanities (533/15). Y.F. and B.K. were supported by European Research Council grant no. ERC-2014-STG-639792, Israeli Science Foundation grant no. ISF-1281/17, and the QuantERA ERA-NET Cofund in Quantum Technologies (project no. 731473). Y.W.X., Z.Y.C., Y.H. and H.Y.H. acknowledge support from the Department of Energy, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, under contract no. DE-AC02-76SF00515 (LAO/STO synthesis), and the Gordon and Betty Moore Foundation’s EPiQS Initiative through grant GBMF4415 (LAO/STO transport characterization).

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D.V.C., Y.F., N.P. and B.K. initiated this work. D.V.C. performed the transport measurements and prepared the GAO/STO samples. Y.W.X., Z.Y.C., Y.H. and H.Y.H. prepared the LAO/STO samples. D.V.C., Y.F. and B.K. performed the scanning SQUID measurements. D.V.C. and Y.F. performed data analysis. D.V.C., Y.F., A.S., Y.Z.C., L.K., N.P. and B.K. interpreted the data. D.V.C. wrote the manuscript with Y.F. and input from all authors.

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Correspondence to N. Pryds or B. Kalisky.

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Christensen, D.V., Frenkel, Y., Chen, Y.Z. et al. Strain-tunable magnetism at oxide domain walls. Nat. Phys. 15, 269–274 (2019). https://doi.org/10.1038/s41567-018-0363-x

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