Visible microactuation of a ferromagnetic shape memory alloy by focused laser beam

We used a focused laser beam to achieve large amplitude and localized controlled actuation in a microstructure made of a ferromagnetic shape memory alloy. Significant deformation (18??m) was achieved at low laser power (20?mW) and the amplitude of actuation could be linearly controlled with the laser power. The rapid mechanical actuation shows no apparent sign of fatigue even after a million continuous oscillatory cycles. As a possible mechanism, we propose that the deformation of structure was induced by a combination of the thermal effect and the magnetic field of the incident laser light. This is possibly the first such reported visual evidence of microactuation of materials due to the optomagnetic field.