Change of GMR parameters in N-ion implanted spin-valve

Giant magnetoresistance (GMR) profiles have been measured as a function of the thickness of pinned NiFe layers for N-ion implanted spin-valve samples. The measured results are analyzed using the double-domain model (DDM), newly introducing the magnetic viscosity effect retarding the domain rotation by the defect or pinning centers. The hysteresis increase of GMR profiles after the ion implantation at θ = 90° can be explained by the magnetic viscosity effect of pinned NiFe layer. The simulation results, well fitted with the measured data, indicate that the N-ion implantation significantly raises the magnetic viscosity effect of the pinned NiFe layer. The magnetic viscosity effect after N-ion implantation exponentially decreases with the thickness of the pinned NiFe layer.