A magnetic write pole having a structure that prevents thermally induced pole tip protrusion. The write head has a return pole with a magnetic pedestal formed at the air bearing surface (ABS) and a back gap at an end opposite the ABS. An electrically conductive write coil having a plurality of turns passes over the return pole. A fill layer of a material having a low coefficient of thermal expansion, such as alumina is disposed between the coil and the pedestal, and may extend over the top of the coil to the back gap. A photoresist coil insulation layer may be provided between the turns of the coil to insulate the turns of the coil from one another. The photoresist coil insulation layer can also extend to the back gap. A write pole, formed above the return pole and coil is magnetically connected with the back gap layer and return pole by a magnetic shaping layer.