Probing magnetism in 2D van der Waals crystalline insulators via electron tunneling.

Klein, D R; MacNeill, D; Lado, J L; Soriano, D; Navarro-Moratalla, E; Watanabe, K; Taniguchi, T; Manni, S et al. · Science · 2018

basic_science · Level V

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Abstract

Magnetic insulators are a key resource for next-generation spintronic and topological devices. The family of layered metal halides promises varied magnetic states, including ultrathin insulating multiferroics, spin liquids, and ferromagnets, but device-oriented characterization methods are needed to unlock their potential. Here, we report tunneling through the layered magnetic insulator CrI<sub>3</sub> as a function of temperature and applied magnetic field. We electrically detect the magnetic ground state and interlayer coupling and observe a field-induced metamagnetic transition. The metamagnetic transition results in magnetoresistances of 95, 300, and 550% for bilayer, trilayer, and tetralayer CrI<sub>3</sub> barriers, respectively. We further measure inelastic tunneling spectra for our junctions, unveiling a rich spectrum consistent with collective magnetic excitations (magnons) in CrI<sub>3</sub>.