High signal output in current-perpendicular-to-the-plane giant magnetoresistance sensors using In–Zn–O-based spacer layers

Abstract

We report current-perpendicular-to-the-plane giant magnetoresistance (CPP-GMR) sensors with a conductive Ag/In–Zn–O (IZO)/Zn trilayer as the spacer layer. Magnetoresistance ratios as high as 26% at resistance–area product (RA) = 60–120 mΩ µm2 were obtained in thin, polycrystalline spin valves suitable for modern read sensors of hard disk drives (HDDs). The large CPP-GMR values are attributed to the large spin-dependent scattering at the interfaces of the ferromagnet/IZO-based spacer junctions. The maximum voltage output of sensors with Ag/IZO/Zn spacers was ΔVmax = 11.3 mV, significantly larger than that observed for metallic AgSn spacers (2.3 mV). Such improved properties are important for HDD read heads with recording densities larger than 1 Tbit/in.2.