Development of magnetostrictive foil with nano multilayer-hetero magnetic domain driven by lower magnetic field

1.超磁致伸缩Fe-Ga合金由于其高的磁致伸缩速度和巨大的磁致伸缩应力，有望成为驱动/传感器材料。为了开发低磁场诱导的磁致伸缩材料，我们采用磁控溅射方法制备了磁致伸缩（正磁致伸缩/负磁致伸缩）双晶层，即Fe_<80>Ga_<20>（146 μm）/ Ni（14 μm）薄膜。采用快速凝固法制备了Fe_<80>Ga_3<20>薄带。采用光杠杆法测量了该薄膜的磁致伸缩特性。在40 kAm/cm的低稳定磁场下，长度为22 mm的箔的上部的位移为530 pin，<-1>并且表现出：小滞后。这些磁致伸缩特性在低频交变磁场下也能保持。此外，在机械共振频率的位移的箔表现出一个峰值，并达到2.0毫米，在弱磁场为50 Oe.2。将磁致伸缩双晶薄膜应用于微气阀。通过施加平行于长度方向的磁场，可以使这些悬臂梁式致动器弯曲。在500 Oe下致动器的一个点位移约300 μm，由磁致伸缩致动器构成的气阀可通过磁场遥控开关动作。在将磁场增加到3500 e时，气体的流速可以被驱动50到Occ/min<-1>。施加磁场后的响应时间低于0.15秒，非常快：

1. Giant magnetostrictive Fe-Ga alloys are expected as actuator/sensor materials with high respective velocity and huge stress created by the magnetostriction. In order to develop magnetostrictive material induced by low magnetic field, we investigated magnetostrictive (positive magnetostriction / negative magnetostriction) bimorph-layers, that is, Fe_<80>Ga_<20> ribbon (146 μm)/ Ni (14 μm) film by magnetron sputtering system. The Fe_<80>Ga_<20> ribbon was prepared by rapidly solidification. Magnetostrictive property of the cantilever-type foil was measured using an optical lever method. Displacement of the upper part of the foil with length of 22 mm was 530 pin under low steady magnetic field of 40 kAm^<-1> and exhibits.- little hysteresis. These magnetostrictive properties also are maintained under low frequency of alternating magnetic field. Moreover, the displacement of the foil at the mechanical resonance frequency exhibits a peak and reaches to 2.0 mm at week magnetic field of 50 Oe.2. The, magnetostrictive bimorph-layers was applied to micro-gas valve. These cantilever-type actuators can be bent by applying magnetic field parallel to length. A point of the actuator displaced about 300 μm under 500 Oe. The opening and closing action of a gas-valve consisted of magnetostrictive actuator can be controlled remotely by magnetic fields. Flow rate of gas can be driven 50 to 0 cc min^<-1> upon increasing magnetic field to 3500e. Response time after applying of magnetic field is below 0.15 sec, it is fast: