Asymmetric current-driven switching of synthetic antiferromagnets with Pt insert layers

A perpendicularly magnetized synthetic antiferromagnetic structure is a promising alternative to a single ferromagnetic layer in spintronic applications because of its low net magnetization and high thermal stability. In this work, the ferromagnetic layers in the synthetic antiferromagnetic structure are simplified to 'soft' Co70Fe30 layers with the aid of ultrathin Pt insert layers between the ferromagnetic layers and the exchange coupling Ru layer to lower the energy consumption. In the current-driven manipulation of the magnetization, asymmetric switching loops are observed, which originate from the edge domain walls induced by the growth of the electrode pads. The edge domain walls preserved beneath the electrode pad help the switching process skipping the nucleation stage, lowering the critical current density to the order of 106 A cm-2. The present work broadens the choice of ferromagnetic layers for building an SAF structure and highlights a new way to utilize the synthetic antiferromagnetic structure as a building block in low-energy-consuming spintronic devices.