A dual magnetic tunnel junction (MTJ) sensor is provided with a
longitudinal bias stack sandwiched between a first MTJ stack and a second
MTJ stack. The longitudinal bias stack comprises an antiferromagnetic
(AFM) layer sandwiched between first and second ferromagnetic layers. The
first and second MTJ stacks comprise antiparallel (AP)-pinned layers
pinned by AFM layers made of an AFM material having a higher blocking
temperature than the AFM material of the bias stack allowing the AP-pinned
layers to be pinned in a transverse direction and the bias stack to be
pinned in a longitudinal direction. The demagnetizing fields of the two
AP-pinned layers cancel each other and the bias stack provides flux
closures for the sense layers of the first and second MTJ stacks.
