Ferromagnetic Shape Memory Microactuators

The technologies for fabrication, micromachining and integration of Ni-Mn-Ga thin films are developed in order to create novel microactuators and sensors. These devices simultaneously make use of the electrical, thermoelastic and ferromagnetic properties of the thin films allowing a new level of multifunctionality and, as a consequence, particularly compact designs. By adjusting the Ni-content of the thin films, the martensitic and ferromagnetic transformation temperatures are tuned close to each other above 373 K, which has important consequences on the device performance such as actuation stroke and response time. This article focuses on the mechanisms, fabrication technologies as well as typical performance characteristics of Ni-Mn-Ga microvalves and microscanners. The present state-of-the-art of FSMA microactuators is highlighted.