Spin-valve structures exchange biased with a-Tb0.23Co0.77 layers

Abstract
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 Å thick a‐Tb0.23Co0.77 layer. Exchange fields between 50 and 250 Oe were achieved with TbCo thicknesses below 400 Å, for a pinned Permalloy layer 150 Å thick. The exchange fields are strongly dependent on substrate bias. The magnetoresistance of these structures reaches 4.5% when thin Co layers are added at the NiFe/Cu interfaces.