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Magnetomechanical Properties of Polycrystalline Ni-Mn-Ga Thin Film Actuators
|Anurag Agarwal 2,4, Manfred Kohl 2, Volodymyr A. Chernenko 3, M. Ohtsuka 1
1. Tohoku University, Sendai, Japan
A series of experiments have been performed on bending, tensile and bridge actuators of polycrystalline Ni-Mn-Ga thin films, to observe the effects of applied tensile load and varying magnetic field on the field-induced strain in martensitic state. Ni-Mn-Ga thin films of 10µm thickness have been deposited by magnetron sputtering. The actuators have been fabricated by photochemical micromachining and MEMS-based interconnection technology. An interesting enhancement of magnetostrain is noticed for both, tensile and bridge actuators. For tensile actuators, the maximum magnetostrain is evaluated to -2470 ppm at 0.5 T and a stress of 7 MPa, which is considerably larger than the ordinary magnetostriction of -240 ppm for a reference thin film of 1 µm thickness. A trend of decrease in magnetostrain is noticed for increasing load. The maximum magnetostrain for the bridge actuators is estimated to -710 ppm for a magnetic field of 0.5 T and a stress of 13 MPa. In this case, an increase of magnetostrain is observed for increasing load.
Presentation: oral at E-MRS Fall Meeting 2005, Symposium C, by Anurag Agarwal
See On-line Journal of E-MRS Fall Meeting 2005
Submitted: 2005-05-20 15:35 Revised: 2009-06-07 00:44