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Giant magnetoresistance (GMR) type Co-Cu multilayers and exchange-biased spin-valve (EBSV) type Co-Cu-Co tri-layers are fabricated by sputtering with a thin layer of Ag inserted between Co and Cu as a surface modifier (SM). Their magnetoresistances (MR) are measured in both current-perpendicular-to-plane (CPP) and current-in-plane (CIP) configurations. In all situations, the size of the MR change decreases as the Ag SM is introduced, and the effect is interface related. Index Terms--Current-in-plane (CIP), current-perpendicular-to-plane (CPP), exchange-biased spin-valve (EBSV), giant magnetoresistance (GMR), surface modifier.

The dependence of magnetotransport on field orientation is an important issue in spintronics-related devices where the applied field is not necessarily in the ideal field-in-plane (FIP) geometry. In this study, we perform tunneling magnetoresistance (TMR) measurements on Co-Al2 O3-CoFe-NiFe spin-dependent tunnel (SDT) junctions prepared at different conditions with varying field orientation ranging from FIP to field-perpendicular-to-plane (FPP). The TMR ratio decreases drastically, whereas the switching field of Co increases when the field direction is set close to FPP. Furthermore, in a situation near FPP, a peculiar TMR looping behavior is observed for one set of samples. Interface effect is thought to be related. [ABSTRACT FROM AUTHOR]