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Martensitic transformation in NiMnGa/Si bimorph nanoactuators with ultra-low hysteresis

Lambrecht, F.; Sagardiluz, N.; Gueltig, M.; Aseguinolaza, I. R.; Chernenko, V. A.; Kohl, M.

Abstract (englisch):
We report on the fabrication and in-situ characterization of temperature-dependent electrical resistance and deflection characteristics of free-standing NiMnGa/Si bimorph cantilevers with a NiMnGa layer thickness of 200 nm and a minimum lateral width of 50 nm. The martensitic transformation in the initial NiMnGa/Si bimorph films and nanomachined NiMnGa/Si bimorph cantilevers
proceeds in a wide temperature range with a hardly detectable temperature hysteresis width below 1K. This remarkable behavior is ascribed to the internal stress in the bimorph system that
exceeds the stress limit of the critical point terminating the stress-temperature phase diagram as it is known for ferromagnetic shape memory alloys. Temperature-dependent deflection characteristics
reveal a competition between the bimorph effect and the shape memory effect, causing beam deflection in opposite directions. The observation of the shape memory effect strongly depends on
the NiMnGa/Si thickness ratio, causing a maximum deflection change per beam length of 3% in agreement with finite element simulations.


Zugehörige Institution(en) am KIT Institut für Mikrostrukturtechnik (IMT)
Publikationstyp Zeitschriftenaufsatz
Jahr 2017
Sprache Englisch
Identifikator DOI: 10.1063/1.4984058
ISSN: 0003-6951, 1077-3118
KITopen ID: 1000070125
HGF-Programm 43.22.01; LK 01
Erschienen in Applied physics letters
Band 110
Heft 21
Seiten Art.Nr. 213104
URLs http://aip.scitation.org/doi/10.1063/1.4984058
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