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Disentangling the magnetic proximity effect in topological insulators with Mg(Al,Fe)<sub>2</sub>O<sub>4</sub>/Bi<sub>2</sub>Se<sub>3</sub> thin films

ORAL

Abstract

Magnetic topological insulators (TIs) have attracted attention as platforms for hosting the quantum anomalous Hall effect, characterized by the emergence of a quantum Hall effect in zero magnetic field and dissipation-less conduction. Magnetic TIs have been achieved through the addition of magnetic dopants to TIs or by a magnetic proximity effect induced in TIs due to an adjacent ferromagnet. Anomalous Hall effect, magnetoresistance, and polarized neutron reflectometry (PNR) measurements have been used as evidence of a magnetic proximity effect in a TI. In this talk, we have studied heterostructures of the ferromagnetic insulator Mg(Al,Fe)2O4 and TI Bi2Se3 to explore a possible magnetic proximity effect. They exhibit a nonlinear Hall effect that can be interpreted in terms of an anomalous Hall effect or multiband carriers in the TI, especially when the ferromagnetic insulator has an in-plane easy axis. Polarized neutron reflectometry provides two possible magnetic profiles – a sharp interface with a proximity effect and a highly disordered interface with no proximity effect. Further measurements of interface quality are required to prove the existence of induced magnetism in TIs.

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Presenters

  • Lauren Riddiford

    Stanford Univ, Applied Physics, Stanford University

Authors

  • Lauren Riddiford

    Stanford Univ, Applied Physics, Stanford University

  • Alexander Grutter

    National Institute of Standards and Technology, Center for Neutron Research, National Institute of Standards and Technology, NIST Center for Neutron Research, NIST, NIST Gaithersburg

  • Timothy S Pillsbury

    Pennsylvania State University, Physics, The Pennsylvania State University, Physics, Pennsylvania State University, The Pennsylvania State University

  • Nitin Samarth

    Pennsylvania State University, Department of Physics, The Pennsylvania State University, Physics, The Pennsylvania State University, Physics, Pennsylvania State University, The Pennsylvania State University

  • Yuri Suzuki

    Department of Applied Physics, Stanford University, Applied Physics, Stanford University, Stanford University, Stanford Univ