A magnetic read/write head having a heating element to induce a desired amount of thermal protrusion in the read and write elements to control the fly height of the read and write elements over a magnetic medium. The heating element is connected with circuitry that provides an electrical bias (voltage or current) that switches polarity in order to prevent electromigration, thereby greatly increasing the life of the heating element. The polarity of the heating element can be switched upon the occurrence of a predetermined event such as between read or write events or upon activating deactivating the disk drive device or could be performed at regular, predetermined time intervals. The dual polarity bias could also be provided by applying an AC bias to the heating element.