Electro migration occurs when some of the momentum of a moving electron is transferred to a nearby activated ion. When a current moves through a conductor, a magnetic field is generated, and this causes ions to move from their original positions. Breaks or gaps can develop in the conducting material, preventing the flow of electricity. Electro migration can also induce the atoms to pile up and drift towards nearby conductors, causing shorts. Both situations can lead to a malfunction of the circuit.