Development of ferromagnetic shape memory nanoactuators

This paper presents the fabrication and actuation of first freestanding in-plane nanostructures of a ferromagnetic shape memory alloy (FSMA) by combining magnetron sputtering of epitaxial FSMA thin films, a Cr-based sacrificial layer technology, electron beam lithography, and ion beam etching. The viability of the process is demonstrated by mechanical deflection and thermo-elastic performance tests. Temperature dependent electrical resistance measurements of double-beam test structures with critical dimensions of 200 nm show a full hysteresis. A reversible out-of-plane actuation of 500 nm is achieved, which is based on the thermally induced martensitic transformation of the Ni-Mn-Ga.