A method for providing a self-pinned differential GMR sensor and
self-pinned differential GMR sensor. The differential GMR head includes
two self-pinned GMR sensors separated by a gap layer. The gap layer may
act as a bias structure to provide antiparallel magnetizations for the
first and second free layers without using an antiferromagnetic layer.
The gap layer may include four NiFe ferromagnetic layers separated with
three interlayers. The gap may also be formed to include a structure
defined by Ta/Al.sub.2O.sub.3/NiFeCr/CuOx. One of the pinned layer may
include three ferromagnetic layers so that the top ferromagnetic layer of
the bottom pinned layer and the bottom ferromagnetic layer of the bottom
pinned layer have a magnetization 180.degree. out of phase. The
self-pinned GMR sensors may include synthetic free layers that includes a
first free sublayer, an interlayer and a second free sublayer that are
biased 180.degree. out of phase.