Pulsed magnetic field-induced actuation of Ni–Mn–Ga single crystals

Abstract

The field-induced actuation of Ni–Mn–Ga single crystals through twin-boundary motion has been demonstrated with magnetic fieldpulses of various intensities lasting 620 μs. It is shown that the complete field-induced strain can be obtained in 250 μs, which implies the possibility of full 6% cycling of Ni–Mn–Ga at 2 kHz, for crystals having dimensions in the range of a few millimeters. The final extension increases with the peak driving force, which is not linear with the field and saturates at 7.85 kOe. An increase of the field beyond the saturation level produces no additional strain but reduces the time for field-induced detwinning.