A first magnetic sublayer includes a region containing X (e.g., Cr), which extends
from the interface with an antiferromagnetic layer toward a nonmagnetic intermediate
sublayer, and a region not containing X, which extends from the interface with
the nonmagnetic intermediate sublayer toward the antiferromagnetic layer. Consequently,
both the unidirectional exchange bias magnetic field (Hex*) in the pinned magnetic
layer and the rate of change in resistance (R/R) can be improved.
