title: Stable microwave-assisted magnetization switching for nanoscale exchange-coupled composite grain.
abstract: Magnetization mechanisms of nanoscale magnetic grains greatly differ from well-known magnetization mechanisms of micrometer- or millimeter-sized magnetic grains or particles. Magnetization switching mechanisms of nanoscale exchange-coupled composite (ECC) grain in a microwave field was studied using micromagnetic simulation. Magnetization switching involving a strongly damped or precessional oscillation was studied using various strengths of external direct current and microwave fields. These studies imply that the switching behavior of microwave-assisted magnetization switching of the ECC grain can be divided into two groups: stable and unstable regions, similar to the case of the Stoner-Wahlfarth grain. A significant reduction in the switching field was observed in the ECC grain when the magnetization switching involved precessional oscillations similar to the case of the Stoner-Wohlfarth grain. This switching behavior is preferred for the practical applications of microwave-assisted magnetization switching.
authors.affiliation: Graduate School of Information Science and Electrical Engineering, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japan. t-tanaka@ed.kyushu-u.ac.jp.
authors.forename: Terumitsu
authors.initials: T
authors.lastname: Tanaka
authors.forename: Shota
authors.initials: S
authors.lastname: Kashiwagi
authors.forename: Yoshitoki
authors.initials: Y
authors.lastname: Furomoto
authors.forename: Yuto
authors.initials: Y
authors.lastname: Otsuka
authors.forename: Kimihide
authors.initials: K
authors.lastname: Matsuyama