Tunnel MR head with long stripe height stabilized through side-extended bias layer

In a tunnelmagneto resistive (TMR) device, free stack sublayers are separated by an intermediate spacer layer that serves to ensure a uniform circumferential magnetization in the free stack, counterbalancing orange-peel coupling by anti ferromagnetic exchange coupling. On top of the upper free stack sublayer a thin upper anti ferromagnetic layer may be formed to act as a hard bias layer and suppress side reading. The thickness of the upper AFT layer is established to tune sensor sensitivity to external fields as well as to promote greater sensor sensitivity.