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

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 m Omega mu m(2) 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 Delta V-max = 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). (C) 2015 The Japan Society of Applied Physics