Technical importance of multi-ferroic approach for designing advanced
multi-functional actuator/sensors based on a mutual coupling effect between ferroic material
elements is pointed out for intelligent/smart technology. Two types of multi-ferroic
actuator/sensor devices. i.e. (1) magnetically driven composite actuator and (2)
multi-functional surface acoustic wave (SAW) sensor by MEMS are presented. First, a
large-scale robust composite actuator is the composite structure which is reinforced by the
superelastic fiber or lamellar of shape memory alloys (TiNi) in the ferromagnetic metal (Ni)
matrix. This multi-ferroic composite can be driven with high speed as well as considerably
enhanced strain by applying a wireless magnetic field. Secondarily, multi-functionally
designed, multi-ferroic senor device using surface acoustic wave (SAW) is introduced. On the
surface part between IDTs, environmentally active material films such as SMA, FSMA,
magnetostrictive alloy etc. are formed by magnetron-sputtering. Various environmental
sensing parameters i.e. temperature, magnetic field strength, stress, loading hysteresis and
internal damage etc. can be evaluated nondestructively from the signal analysis of amplitude
and phase change of SAW. Consequently, these results show the promising new types of
multi-functional composite actuator and sensor based on multi-ferroic effect.
Dispersion feature in arbitrary direction of surface acoustic wave applied to property characterization of ultra-large-scale integrated circuit interconnect films