late reply but usefull for others.
You are using an electro permanent magnet.
An EP magnet vs EM requires a pulse. To make the polarity internal or external(- or +).
Just send a + pulse or - pulse to switch between magnet on and off.
EP magnets aka holding or sucking magnets do have a down fall. They usually require a capacitor as the pulse is a higher voltage.
Also They are not the best vibration magnets aka like a pager actuator.