Magnetoresistance enhancement of amorphous CoNbZr-buffered magnetoresistive multilayers

Amorphous CoNbZr alloys are thermally stable and thus have been intensively studied as soft layers of a pseudo-spin-valve (PSV). By depositing a wedge-shaped Co inset layer (IL) between the CoNbZr and Cu layer, we were able to simultaneously fabricate CoNbZr(t_CNZ)/Co(0-3 nm)/Cu/Co PSVs with various CoNbZr and Co IL thicknesses. We have investigated the dependence of magnetic properties, giant magnetoresistance (GMR) effect, and microstructure on the thickness of the amorphous CoNbZr buffer layer. The GMR enhancement behaviour of the PSVs with different CoNbZr thickness was also studied along the inset Co wedge. By optimizing the thickness of CoNbZr and Co IL, a maximum GMR ratio of 7% was obtained in the stack of CoNbZr(4 nm)/Co(1.2 nm)/Cu(2.2 nm)/Co(4 nm).