A method to form a passivation layer using an electrochemical process over a MR Sensor so that the passivation layer defines the MR track width. The passivation layer is formed by anodizing the MR sensor. The passivation layer is an electrical insulator (preventing Sensor current (I) from shunting through the overspray) and a heat conductor to allow MR heat to dissipate away from the MR sensor through the overspray. The method comprises: forming a passivation layer on the MR sensor; the passivation layer formed using an electrochemical process. Then we spinning-on and printing a lift-off photoresist structure over the passivation layer. The passivation layer is etched to remove the passivation layer not covered by the lift-off structure thereby defining a track width of the MR sensor. Then we deposit a lead layer over the passivation layer and MR sensor. The lift-off structure is removed where by the passivation layer defines a track width. The passivation layer is an electrical insulator that prevents sensor current (I) form shunting through overspray layers while allowing heat to dissipate through to the lead layer.