Magnetoresistive Effects in Co/Pt-Based Perpendicular Synthetic Antiferromagnets

In this study, Co/Pt based perpendicular synthetic antiferromagnetic (p-SAF) structures with Ru interlayers are investigated with regard to their magnetotransport properties. The p-SAF structures are varied in their number of Co/Pt multilayer (ML) stacks and Ru interlayers, and are examined for changes in their magnetoresistive effects. The alignment of magnetization directions of the MLs in the ML/Ru/ML stacks of the p-SAF generates a giant magnetoresistance effect (GMR), while the anisotropic magnetoresistance effect (AMR) at each ML further influences the resistance of the system. The GMR is found to increase linearly with the number of Ru interlayers. To extract contributions from the AMR, a simple model is proposed, which explains the observed transfer curves where both effects are taken into account. For the AMR amplitude, it is observed that longitudinal AMR contributions decrease with increasing numbers of Co layers in the p-SAF, whereas transverse components remain constant. While the highest GMR effects are measured at low temperatures, only longitudinal AMR contributions appear to be significantly affected by the measurement temperature.