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

Abstract

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 (J(1)) between P1 and P2 layers = - 1.5 erg/cm(2), (ii) the exchange biasing energy between P1 and IrMn layer (J(eb)) = 0.13 erg/cm(2), (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 = 40 Oe. 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. J(1) 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. (C) 2002 Elsevier Science B.V. All rights reserved.