Low-level bistability has been observed in the output from a recently developed novel magnetometer. It is not known whether this behavior is associated with the torsion fiber of the instrument or with the Earth's magnetic field. Whatever its cause, this form of complexity is not widely known.
@article{arxiv.physics/0207063,
title = {Bistability of a Torsion Magnetometer},
author = {Randall D. Peters},
journal= {arXiv preprint arXiv:physics/0207063},
year = {2007}
}