Magnetic trap effect to restrict motion of self-powered tiny liquid metal motors

We reported a phenomenon that the magnetic field can make up a boundary to restrict motion of the aluminum powered liquid metal motor. For the droplet motors with diameter below 1 mm, such magnetic trap effect will be strong enough to bounce them off the boundary. We attributed the effect to the electromagnetic mechanism. Owing to the Lorentz force, the high magnetic field will break up the directional running of the motor. The more aluminum added in the metal droplet, the stronger the trap effect. This phenomenon suggests an important way to control behavior of the liquid metal motors.