A magnetic head assembly has a read head that includes a sensor wherein
the sensor includes a self-pinned antiparallel (AP) pinned layer
structure, a ferromagnetic free layer structure that has a magnetic
moment that is free to rotate in response to signal fields and a spacer
layer which is located between the free layer and AP pinned layer
structures. The self-pinned AP pinned layer structure includes first and
second antiparallel (AP) pinned layers, an antiparallel coupling (APC)
layer located between and interfacing the first and second AP pinned
layers wherein the second AP pinned layer is located between the first AP
pinned layer and the spacer layer. The first AP pinned layer is composed
of cobalt platinum chromium (CoPtCr).