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Ferromagnetic Shape Memory Microscanner with Large Deflection Angles

Daniel Brugger ,  Manfred Kohl ,  Berthold Krevet 

Forschungszentrum Karlsruhe, IMT, Postfach 3640, Karlsruhe 76021, Germany


Ferromagnetic shape memory alloys (FSMAs) experienced a widespread research boom as they exhibit a unique combination of high energy densities, thermoelastic and ferromagnetic properties. Of particular interest have been the Heusler ferromagnetic shape memory alloys Ni-Mn-Ga, which in single crystalline state show the giant magnetostrain effect. Currently, thin film technology is being developed intensively in order to pave the way for applications in microsystems and nanotechnology. For engineering of novel devices, test systems need to be developed and investigated with respect to their spatially and time-resolved physical behaviour in order to clarify the underlying fully coupled thermo-magneto-mechanical material properties.
In the present work, a Ni-Mn-Ga microscanner is used as a test system. Previously, it has been demonstrated that this system allows the simultaneous actuation in two opposite directions by making use of both the ferromagnetic transition and martensitic transformation. The stationary and time-resolved motion of the microscanner is studied experimentally and coupled finite element simulations are performed to clarify the complex implications of the thermal, mechanical and magnetic material properties. The experiments reveal a complex driving power and frequency dependence of the scanning angle. Infrared microscopy investigations are in line with coupled finite element simulations of temperature profiles. Thus, cut-off frequencies are determined theoretically and experimentally. Typical cut-off and resonance frequencies are 60 and 150 Hz, respectively. Based on experimental data, the magnetic field and magnetic force distribution in the system is analyzed.


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Presentation: oral at E-MRS Fall Meeting 2005, Symposium C, by Daniel Brugger
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-05-19 10:56
Revised:   2009-06-07 00:44