The effect of stress upon the magnetic properties of ferromagnetic materials has been known and studied for many years. The name usually associated with this is Villari1. "Matteucci discovered that pulling or stretching a ferromagnetic rod changes its magnetic induction. Villari, however, with greater refinement of method found that if an icon rod is stretched when weakly magnetized its magnetic induction will be increased, whereas stretching the same rod in a strong field its magnetic induction will be decreased. This is known as the Villari reversal effect."
Proceedings of the Iowa Academy of Science
©1954 Iowa Academy of Science, Inc.
Gale, Grant O.
"An Elastomagnetic Effect,"
Proceedings of the Iowa Academy of Science, 61(1), 330-333.
Available at: https://scholarworks.uni.edu/pias/vol61/iss1/39