SPIN-VALVE STRUCTURES EXCHANGE BIASED WITH A-TB0.23CO0.77 LAYERS

Spin-valve structures, glass/NiFeI/Cu/NiFeII/a-TbCo/Cu, were prepared where the pinned Permalloy layer is exchanged biased by a 200 to 400 a ngstrom thick a-Tb0.23Co0.77 layer. Exchange fields between 50 and 250 Oe were achieved with TbCo thicknesses below 400 angstrom, for a pinn ed Permalloy layer 150 angstrom thick. The exchange fields are strongl y dependent on substrate bias. The magnetoresistance of these structur es reaches 4.5% when thin Co layers are added at the NiFe/Cu