In situ and ex situ observation of spin valves obtained by ion-beam deposition

“Bottom” spin valves of the type NiO/15 Å NiFe/15 Å Co/t_Cu Cu/20 Å Co/50 Å NiFe were prepared by ion-beam deposition (IBD) on a Si(100)/NiO substrate. It is found that cleaning the substrates by ion-beam etching prior to the deposition of the multilayer has a significant influence on the magnetic properties of the spin valve. In particular, longer etching leads to a decrease in the exchange field and an increase in the coercivity of the pinned layer, without affecting the GMR ratio. A maximum GMR of 11.2% at room temperature is obtained for t_Cu=20 Å and 240 s etching time. The NiO substrate before and after ion-beam etching has been studied by atomic force microscopy (AFM). No significant change in roughness is observed, but the etched substrate shows smaller features