Weakly coupled GMR sandwiches

Thin film structures comprised of two magnetic films sandwiching a nonmagnetic conductor can have magnetoresistance several times larger than conventional anisotropic magnetoresistance materials. If the coupling between magnetizations in the two films is sufficiently small (either parallel or antiparallel), the saturation magnetic field can be sufficiently small for improved read heads. Magnetoresistances, coupling fields, sheet resistivities, current density effects, thermal limits, and magnetostrictions of these structures are described. No fundamental restrictions are found for using these sandwiches in magnetic head applications.< >