Micromagnetic Evaluation of Size Effects on the Critical Curves of Synthetic Antiferromagnetic Structures

In many applications in which synthetic antiferromagnetic (SAF) structures are used, the most intricate problem is to design a magnetic field sequence to safely switch the AF coupled magnetic moments. In this paper, we analyze the switching of a SAF structure under a magnetic field pulse using the concept of critical curve (CC). To observe the size effects on the CCs, we have used a full micromagnetic simulation based on Magpar software package. The results have been compared with a simulation of the CCs with a simplified model using two macrospins coupled antiferromagnetically with the dynamics described by the Landau-Lifshitz-Gilbert equation. The differences between the two ways of simulation the same switching process are presented and discussed.