Magnetic multilayer devices that exploit magnetoresistance are the backbone of magnetic sensing and data storage technologies. Here we report novel multiple-spin-filter magnetic tunnel junctions (sf-MTJs) based on van der Waals (vdW) heterostructures in which atomically thin chromium triiodide (CrI3) acts as a spin-filter tunnel barrier sandwiched between graphene contacts. We demonstrate tunneling magnetoresistance which is drastically enhanced with increasing CrI3 layer thickness, reaching a record 19,000% for magnetic multilayer structures using four-layer sf-MTJs at low temperatures. These devices also show multiple resistance states as a function of magnetic field, suggesting the potential for multi-bit functionalities using an individual vdW sf-MTJ. Using magnetic circular dichroism measurements, we attribute these effects to the intrinsic layer-by-layer antiferromagnetic ordering of the atomically thin CrI3. Our work reveals the possibility to push magnetic information storage to the atomically thin limit, and highlights CrI3 as a superlative magnetic tunnel barrier for vdW heterostructure spintronic devices.
@article{arxiv.1801.08679,
title = {Giant Tunneling Magnetoresistance in Spin-Filter van der Waals Heterostructures},
author = {Tiancheng Song and Xinghan Cai and Matisse Wei-Yuan Tu and Xiaoou Zhang and Bevin Huang and Nathan P. Wilson and Kyle L. Seyler and Lin Zhu and Takashi Taniguchi and Kenji Watanabe and Michael A. McGuire and David H. Cobden and Di Xiao and Wang Yao and Xiaodong Xu},
journal= {arXiv preprint arXiv:1801.08679},
year = {2018}
}