Parametric sensitivity analysis on the giant magnetoresistive characteristics of synthetic antiferromagnet-based spin-valves

A series of static calculations based on the Landau-Lifschitz-Gilbert equation incorporating a single-domain multilayer model applied on synthetic antiferrimagnet (SyAF) based spin-valve structures was carried out to investigate their giant magnetoresistive (GMR) transfer behaviors. The typical multilayer structure comprises NiFe (3.2)/CoFe (1.6)/Cu (2.8)/CoFe (P2, 3.0)/Ru (0.7)/CoFe (P1, 1.5)/IrMn (9.0) (in nm). Four fitting parameters were obtained from the comparisons between the calculated and experimental results: (i) the indirect exchange coupling energy (J₁) between P1 and P2 layers=-1.5erg/cm², (ii) the exchange biasing energy between P1 and IrMn layer (J_eb)=0.13erg/cm², (iii) the relative GMR contribution (R) due to the angular difference of magnetizations in CoFe (P2)/Ru/CoFe (P1) trilayers=3%, and (iv) the induced uniaxial anisotropy value (H_ua) of CoFe layers=40Oe. These values appear reasonable and are within the range of those reported in the literatures, indicating that the present single-domain model works well. In order to examine how these parameters affect the MR transfer curve, one of these parameters was systematically varied while the rest were fixed. J₁ was found to be mainly related with the saturation field (H_s) and the field at which the maximum sub-peak MR ratio (H_sub). J_eb influenced on the effective exchange field (H_ex.eff). It was also observed that R increases the total MR ratio, but the MR transfer curve was less affected by H_ua.