Current-perpendicular-to-the-plane spin-valve films with iron-added magnetite layers

A current-perpendicular-to-the-plane (CPP)-spin-valve sensor with iron-added magnetite layers (lMLs) was investigated. We prepared bottom synthetic-pin spin-valve films with CoFe/IML/CoFe sandwiched layers as both free layers and pinned layers. The slope of resistance-change-area product (Delta RA) versus IML thickness is around 0.5-0.6 Omega mu m(2)/nm, and this indicates that using IMLs results in large bulk scattering. Magnetite and iron grains were observed in transmission electron microscopy images even in a 2-nm-thick IML in a CPP giant magnetoresistance structure. As a result, Delta RA up to 2-2.5 m Omega mu m(2) and MR ratio of 2.0%-2.6% at RA of 0.08-0.1 Omega mu m(2) were obtained by using IML in CPP-spin-valve films. (c) 2005 American Institute of Physics.