Disclosed herein is a magnetoresistive structure, for example useful as a
spin-valve or GMR stack in a magnetic sensor, and a fabrication method
thereof. The magnetoresistive structure uses twisted coupling to induce a
perpendicular magnetization alignment between the free layer and the
pinned layer. Ferromagnetic layers of the free and pinned layers are
exchange-coupled using antiferromagnetic layers having substantially
parallel exchange-biasing directions. Thus, embodiments can be realized
that have antiferromagnetic layers formed of a same material and/or
having a same blocking temperature. At least one of the free and pinned
layers further includes a second ferromagnetic layer and an insulating
layer, such as a NOL, between the two ferromagnetic layers. The
insulating layer causes twisted coupling between the two ferromagnetic
layers, rotating the magnetization direction of one 90 degrees relative
to the magnetization direction of the other.