Perpendicular magnetic tunnel junctions based on MgO/CoFeB structures are of particular interest for magnetic random-access memories because of their excellent thermal stability, scaling potential, and power dissipation. However, the major challenge of current-induced switching in the nanopillars with both a large tunnel magnetoresistance ratio and a low junction resistance is still to be met. Here, we report spin transfer torque switching in nano-scale perpendicular magnetic tunnel junctions with a magnetoresistance ratio up to 249% and a resistance area product as low as 7.0 {\Omega}.{\mu}m2, which consists of atom-thick W layers and double MgO/CoFeB interfaces. The efficient resonant tunnelling transmission induced by the atom-thick W layers could contribute to the larger magnetoresistance ratio than conventional structures with Ta layers, in addition to the robustness of W layers against high temperature diffusion during annealing. The switching critical current density could be lower than 3.0 MA.cm-2 for devices with a 45 nm radius.
@article{arxiv.1708.04111,
title = {Current-induced magnetization switching in atom-thick tungsten engineered perpendicular magnetic tunnel junctions with large tunnel magnetoresistance},
author = {Mengxing Wang and Wenlong Cai and Kaihua Cao and Jiaqi Zhou and Jerzy Wrona and Shouzhong Peng and Huaiwen Yang and Jiaqi Wei and Wang Kang and Youguang Zhang and Jürgen Langer and Berthold Ocker and Albert Fert and Weisheng Zhao},
journal= {arXiv preprint arXiv:1708.04111},
year = {2018}
}