Effects of Boron surface accumulation on the Néel temperature revealed in B-doped Cr<sub>2</sub>O<sub>3</sub> films

ORAL

Abstract

Multi-functional thin films of boron (B) doped Cr2O3 grown by pulsed laser deposition exhibit voltage-controlled and nonvolatile Néel vector reorientation in the absence of a magnetic field. Isothermal toggling of antiferromagnetic states is demonstrated in prototype device structures at CMOS compatible temperatures between 300 K and 400 K. A strict determination of TN is essential but has remained elusive most likely due to a thermally activated runaway effect of the Néel temperature. This behavior can be understood by considering the B-enrichment due to the phenomenon of surface segregation. Cold Neutron Depth Profiling (cNDP), performed at National Institute of Standards and Technology, points at progressing depletion of B in the bulk and B-accumulation near the surface. By using X-ray Photon Spectroscopy and Spin Hall measurements, we demonstrate a shift in TN towards higher values of ≈ 477 K, associated with the increase in B-concentration within an interfacial layer of about 70 nm.

*Financial support by NSF/EPSCoR RII Track-1: Emergent Quantum Materials and Technologies, OIA-2044049 is acknowledged. The research was performed in part in the NNF: NNCI and the NCMN, supported by NSF under ECCS:2025208, and the NRI. Contributions of the National Institute of Standards and Technology are not subject to copyright.

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Presenters

  • Ather Mahmood

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln
    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

Authors

  • Ather Mahmood

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln
    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

  • Jamie L Weaver

    • National Institute of Standards and Technology, Gaithersburg, Maryland, USA 20899

  • Syed Qamar Abbas Shah

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska - Lincoln
    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln

  • Will Echtenkamp

    • University of Nebraska - Lincoln

  • Jeffrey W Lynn

    • National Institute of Standards and Tech

  • Christian Binek

    • University of Nebraska - Lincoln
    • Department of Physics and Astronomy and the Nebraska Center for Materials and Nanoscience, University of Nebraska-Lincoln