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 theta = 90degrees 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. (C) 2002 Elsevier Science B.V. All rights reserved.