Open Access Nano Express

Stable microwave-assisted magnetization switching for nanoscale exchange-coupled composite grain

Terumitsu Tanaka*, Shota Kashiwagi, Yoshitoki Furomoto, Yuto Otsuka and Kimihide Matsuyama

Author Affiliations

Graduate School of Information Science and Electrical Engineering, Kyushu University, Motooka 744, Nishi-ku, Fukuoka 819-0395, Japan

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Nanoscale Research Letters 2013, 8:461  doi:10.1186/1556-276X-8-461

Published: 5 November 2013

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.

Keywords:
Microwave-assisted magnetization reversal; Exchange-coupled composite grain; Micromagnetic simulation