Ultrafast actuation of Ni-Mn-Ga micropillars by pulsed magnetic field

Abstract

We report on the pulsed magnetic field actuation of single crystalline Ni-Mn-Ga cuboid micropillars with dimensions of 40 × 45 × 120 μm3, created by focused ion beam milling followed by electrochemical etching. Based on the experimental and modelled results, we differentiate between type I and type II twin boundary motion in the micropillar, which display about an order difference in actuation velocities. Magnetically-induced reorientation of a micropillar was obtained in less than 5 μs by type II twin boundary motion. Our results suggest the possibility of fabrication of magnetic shape memory microdevices with working frequencies up to 100 kHz.