Giant tunneling magnetoresistance in spin-filter van der Waals heterostructures.

Song, Tiancheng; Cai, Xinghan; Tu, Matisse Wei-Yuan; Zhang, Xiaoou; Huang, Bevin; Wilson, Nathan P; Seyler, Kyle L; Zhu, Lin et al. · Science · 2018

basic_science · Level V

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Abstract

Magnetic multilayer devices that exploit magnetoresistance are the backbone of magnetic sensing and data storage technologies. Here, we report multiple-spin-filter magnetic tunnel junctions (sf-MTJs) based on van der Waals (vdW) heterostructures in which atomically thin chromium triiodide (CrI<sub>3</sub>) acts as a spin-filter tunnel barrier sandwiched between graphene contacts. We demonstrate tunneling magnetoresistance that is drastically enhanced with increasing CrI<sub>3</sub> layer thickness, reaching a record 19,000% for magnetic multilayer structures using four-layer sf-MTJs at low temperatures. Using magnetic circular dichroism measurements, we attribute these effects to the intrinsic layer-by-layer antiferromagnetic ordering of the atomically thin CrI<sub>3</sub> Our work reveals the possibility to push magnetic information storage to the atomically thin limit and highlights CrI<sub>3</sub> as a superlative magnetic tunnel barrier for vdW heterostructure spintronic devices.