Wiktionary
alt. (context physics English) the change of length or shape of a ferromagnetic material when it is magnetized n. (context physics English) the change of length or shape of a ferromagnetic material when it is magnetized
Wikipedia
Magnetostriction (cf. electrostriction) is a property of ferromagnetic materials that causes them to change their shape or dimensions during the process of magnetization. The variation of materials' magnetization due to the applied magnetic field changes the magnetostrictive strain until reaching its saturation value, λ. The effect was first identified in 1842 by James Joule when observing a sample of iron.
This effect causes energy loss due to frictional heating in susceptible ferromagnetic cores. The effect is also responsible for the low-pitched humming sound that can be heard coming from transformers, caused by oscillating AC currents, which produce a changing magnetic field.
Usage examples of "magnetostriction".
And then a cavern where several people sat and just watched a rotating display of exciting gadgets: self-winding vinyl shavers, laminated automatic mattress inflaters, combination spectrometer-tachometers, Old West-style laser guns, disposable artificial epoxy kidneys, solid-state microwave oscillators in decorator colors, electroluminescent diodes in personalized carrying cases, solar-powered nose-hair clippers, princess-style videophones, geodesic teakettles, injectionmolded garlic presses, manually operated cherrystoners, alligator-finished episcopes, magnetostriction ultrasonic generators on patio stands, self-turning kaleidoscopes, robot flatirons, vestpocket bronchoscopes, paisley-surfaced binnacles, miniaturized vacuum cleaners, musical abacuses.
Bolts that held their nuts on by magnetostriction couldn't have those nuts removed by a tool that was nothing but vinyl acetate.