A micromagnetostrictive vibrator using a U-shaped core made of iron-gallium alloy (Galfenol) was investigated. The vibrator consists of a Galfenol core, with a 1mm2 cross section, a length of 5.8mm, and a 0.3mm separation between the prongs of the “U,” driving coils, and an iron yoke to close the magnetic loop. The Galfenol vibrator is superior to the PZT type in its high mechanical strength, low drive voltage requirements, and wide temperature operating range, and compared to our previous cylindrical type vibrator has a simpler construction and higher bandwidth. A displacement of 1.2μm(220ppm) was verified for the prototype with a 5.8mm long Galfenol core; the high magnetostriction >200ppm is inherited from the stress-annealed Galfenol. The displacement was also maintained under a 21MPa tensile stress (1.5kg hanging weight). Incorporation of a Nd–B–Fe magnet into the magnetic circuit successfully shifted the operating point to the linear portion of the magnetostrictive curves. This biasing effect is useful in reducing the drive voltage.

1.
A. E.
Clark
,
M.
Wun-Fogle
, and
J. B.
Restorff
, “
Magnetostrictive properties of body-centered cubic Fe-Ga and Fe-Ga-Al alloy
,”
IEEE Trans. Magn.
37
,
3238
(
2000
).
2.
T.
Ueno
,
E.
Summers
, and
T.
Higuchi
,
Conference Proceeding of the Tenth International Conference on New Actuator (ACTUATOR2006)
,
2006
, pp.
410
413
.
3.
M.
Wun-Fogle
,
J. B.
Restorff
, and
A. E.
Clark
, “
Magnetomechanical coupling in stress-annealed Fe-Ga (Galfenol) alloys
,”
IEEE Trans. Magn.
42
,
3120
(
2006
).
You do not currently have access to this content.