We measured the shot noise in the CoFeB/MgO/CoFeB-based magnetic tunneling junctions with a high tunneling magnetoresistance ratio (over 200% at 3 K). Although the Fano factor in the anti-parallel configuration is close to unity, it is observed to be typically 0.91\pm0.01 in the parallel configuration. It indicates the sub-Poissonian process of the electron tunneling in the parallel configuration due to the relevance of the spin-dependent coherent transport in the low bias regime.
@article{arxiv.1108.4831,
title = {Sub-Poissonian shot noise in CoFeB/MgO/CoFeB-based magnetic tunneling junctions},
author = {Tomonori Arakawa and Koji Sekiguchi and Shuji Nakamura and Kensaku Chida and Yoshitaka Nishihara and Daichi Chiba and Kensuke Kobayashi and Akio Fukushima and Shinji Yuasa and Teruo Ono},
journal= {arXiv preprint arXiv:1108.4831},
year = {2011}
}