New high responsive Fe-Pd magnetostrictive films with high power were developed and prepared by magnetron sputtering. The in-plane magnetization of Fe-Pd thin film was larger than that of the Tb<sub>0.3</sub>Dy<sub>0.7</sub>Fe<sub>2</sub> alloy film. The Fe-Pd magnetostrictive films show large magnetostriction and high magnetostrictive susceptibility at low magnetic field from earth magnetic field to 1 kOe. The high magnetostrictive susceptibility of the Fe-Pd alloy films obtained was appropriate as a remote actuator in low magnetic field. If an ideal Fe-Pd magnetostrictive films are developed to apply the micro-machine, offering the advantages of low cost, lightweight and relatively simple design. In order to
apply these properties to a practical actuator, load dependence of magnetostrictive susceptibility was serious potential problems. In this study, the magnetostrictive susceptibility changes were measured under different loading stresses. As a result, Fe-Pd alloy film showed high magnetostrictive susceptibility under high film loading stress above 50 MPa.
Two kinds of high power actuator film materials prepared by PVD process were developed. One is the The Fe-Pd alloy film, which shows large magnetostriction and high magnetostrictive susceptibility at low magnetic field from earth magnetic field to 1 kOe. Another is the hydrogen storage La-Ni alloy film on a polyimide substrate, which was prepared using a flash evaporation method. The hydrogen storage alloy film showed the reversible shape change, which operated by hydrogen absorption and desorptions. This bi-material actuator was driven by the large volume expansion of hydrogen storage La-Ni alloy film. In this study, the strain changes were measured under different loading stresses. The powers of these two actuator materials were larger than that of Ni-Ti alloy commercially used.
Three types of magnetic field operated shape memory ceramics have been developed. Namely, the shape memory movements can be operated by changes in magnetic flux density. The reversible shape memory effects are often induced by magnetostriction and magnetic field induced twin formation for Fe-Pd alloys. The former shows the precise shape change, whereas the later shows the large shape change expected. The strain value was about 182 ppm at 0.3 kOe at room temperature. The high magnetostrictive susceptibility was detected at low magnetic field. It was higher than that of Tb<SUB>0.3</SUB>Dy<SUB>0.7</SUB>Fe<SUB>2</SUB> thin film developed. The other magnetic field operated shape change is recently found on softening near critical temperature of superconductors. The softening induced shape memory effect (SSME) has been found from 9.5 K to 20 K in pure metallic niobium.