A current-perpendicular-to-the-plane spin-valve (CPP-SV) magnetoresistive
sensor has an improved antiparallel (AP) pinned structure, i.e., a
structure with first (AP1) and second (AP2) ferromagnetic layers
separated by a nonmagnetic antiparallel coupling (APC) layer with the
magnetization directions of AP1 and AP2 oriented substantially
antiparallel. The AP2 ferromagnetic layer (the layer in contact with the
SV spacer layer) is an alloy of a ferromagnetic material and one or more
additive elements of Cu, Au and Ag. The additive elements reduce the
magnetic moment of the AP2 layer, which enables its thickness to be
increased so that its magnetic moment remains close to the magnetic
moment of the AP1 ferromagnetic layer. The thicker AP2 layer allows for
more bulk spin-dependent scattering of electrons which increases the
magnetoresistance of the sensor. An annealed AP2 layer results in more
segregation of the ferromagnetic material grains and the additive element
grains, and thus a further improvement in magnetoresistance as a result
of more interfacial scattering of electrons.