Spin-transfer-induced magnetic domain formation

Abstract

A special nanopillar comprised of a thick top ferromagnetic layer and a thin bottom ferromagnetic layer is fabricated and the transport properties are measured by applying a dc current and an external field. It is shown experimentally that the dc current flowing through the nanopillar could lead to intermediate states between the antiparallel and the parallel magnetic configurations. The intermediate states are characterized to be the result of domain formation in the bottom ferromagnetic layer, due to the injection of spin-polarized current. The results verify that the spin-transfer effect may induce domain formation in a magnetic thin film. It is also suggested that when the spin-transfer effect is utilized to switch the nanopillar device, the domain formation may result in the incomplete magnetization switching.