A magnetoresistive device includes a free ferromagnetic layer; a pinned structure;
and a spacer layer between the free layer and the pinned structure. The pinned
structure may include first, second and third ferromagnetic layers that are ferromagnetically
coupled. The first and third layers are separated by the second layer. The second
layer has a lower magnetic moment than the first and third layers. In the alternative,
the pinned structure may include a single layer of Co50Fe50.