We propose a three-DOF magnetostrictive micro actuator using Iron-Gallium alloy (Galfenol). The actuator consists of two parallel beam structure having a Galfenol core, located at either end of a Galfenol rod of 1 mm square cross-section and length 11 mm, with two orthogonal ditches cut down it of width 0.3 mm. Around the resulting prongs are wound, and the prongs are bonded to an iron end cap to close the magnetic circuit. When current is passed through a coil wound round one of the orthogonal parallel beams, the resulting magnetostriction enables the actuator to bend in two directions. In addition, longitudinal displacement with high frequency bandwidth can be generated by excitation of two or of all four coils. Maximum displacements were observed of 8 to 10 μm in bending and 2.2 μm in the longitudinal direction. This actuator is potentially applicable in machining (drilling), positioning, and in a micro-motor using wobbling or translational motion when powered by a small power supply.
We propose a miniature spherical motor using iron-gallium alloy (Galfenol). This motor consists of four rods of
Galfenol with square cross-section, a wound coil, a permanent magnet, an iron yoke and a spherical rotor placed
on the edge of the rods. The magnetomotive force of the magnet provides bias magnetostriction for the rods
and an attractive force that maintains the rotor on the rods. When currents of 180 deg phase difference flow in
pairs of opposing coils, a torque is exerted on the rotor is by pushing (expansion) and pulling (contraction) of
the rods. Rotation about a single axis is realized by a sawtooth current, such that the rotor rotates with slow
expansion and slips at the rapid contraction. The motor can be fabricated at small sizes and driven with a low
voltage, suitable for application as a microactuator for rotating the camera and mirror in endoscopes.
Melt-spun, rapid solidified Galfenol (Fe-Ga) ribbon sample showed large magnetostriction and good ductility as compared with conventional bulk sample because the ribbon has fine columnar grain which was formed during melt-spinning process. The large magnetostriction is caused by the release of considerable large internal stresses in as-spun ribbon as well as the remained  oriented strong textures after annealing. In order to obtain larger magnetostrictive force than ribbon sample, in this study, magnetostrictive bulky Fe-Ga alloy was fabricated by combining laminate of rapid-solidified ribbons (80 μm in thickness) and spark plasma sintering/joining (SPSJ). SPSJ is characterized by short time and low temperature heating and sintering process. The laminated sample made by SPSJ maintained the unique metallurgical microstructure of polycrystalline texture of columnar grains as well as almost non-equilibrium metastable phase with little existence of ordered precipitations in as-spun ribbons. The excellent sintered sample having large magnetostoriction was obtained under a condition of the compressive stress of 100 MPa at the temperature of 973 K. The magnetostriction depended on compressive pre-stress level for specimen and reached about 100 ppm which was a half of value obtained for the ribbon sample. Furthermore, by following short annealing for this specimen, the magnetostriction increased to 170-190 ppm comparable to the ribbon's value.