Incremental Analysis of Magnetic Domains in Multiple Types of Ferromagnetic CoFe Nanolayer Patterns

Abstract

In this article, the results of incremental analysis on the thickness, aspect ratio, and crystallographic substrate orientation dependence of magnetic domain formation in CoFe nanolayer patterns (NPs) on GaAs (001) substrates by magnetic force microscopy are reported. All the 35 nm thick CoFe NPs show multiple magnetic domains under as‐deposition condition whereas the 13 nm thick CoFe NPs have a single magnetic domain in the case of the patterns with a relatively small size and high aspect ratio. Subsequently, the magnetic fields are applied in the direction parallel to the <110> and <1–10> directions of the substrates to analyze a magnetization switching behavior in the patterns. The results reveal that the magnetic fields required for magnetization switching markedly tend to increase, with decreasing the thickness of the patterns and increasing their aspect ratio. A general tendency is obtained, which a higher magnetic field is needed for a higher aspect ratio and a thinner thickness of the NPs. Even in the case of the patterns with an aspect ratio of unity and a thickness of 35 nm (but, a smaller size), a single magnetic domain is formed at a relatively high applied magnetic field of 1500 Gauss.