Tunneling barrier material for a magnetic recording head

The present invention relates generally to a magnetoresistive sensor for use in a magnetic read head. In particular, the present invention relates to a tunneling magnetoresistive (TMR) read sensor having a low resistance-area (RA) product, yet maintaining a stable magnetoresistive (MR) ratio. A tunneling magnetoresistive stack configured to operate in a current-perpendicular-to-plane mode has a plurality of layers including a barrier layer. The TMR stack has a plurality of layers including a barrier layer, wherein the barrier layer is comprised of an insulating material selected from a group consisting of HfO, HfAlO, ZrO, TiO, TaO or NdO. The TMR stack exhibits a low resistance-area (RA) product, a stable magnetoresistive (MR) ratio, a lower RA product, a higher breakdown voltage of the TMR stack and enhanced thermal stability.