Magnetization reversal in exchange-spring bilayer system under circularly polarized microwave field

TL;DR

This paper investigates the nonlinear magnetization reversal dynamics in exchange-spring bilayer systems under microwave fields, revealing how propagation fields influence reversal and proposing an analytical approximation validated by numerical results.

Contribution

It introduces an analytical approximation for magnetization reversal dynamics in exchange-spring bilayers, validated against numerical simulations, advancing understanding of microwave-assisted reversal.

Findings

Propagation field drives reversal in infinite systems

Reduction of switching field observed numerically

Analytical model matches numerical results

Abstract

Microwave assisted magnetization reversal are studied in the bulk bilayer exchange coupled system. We investigate the nonlinear magnetization reversal dynamics in a perpendicular exchange spring media using Landau-Lifshitz equation. In the limit of the infinite thickness of the system, the propagation field leads the reversal of the system. The reduction of the switching field and the magnetization profile in the extended system are studied numerically. The possibility to study the dynamics analytically is discussed and an approximation where two P-modes are coupled by an interaction field is presented. The ansatz used for the interaction field is validated by comparison with the numerical results. This approach is shown to be equivalent to two exchange coupled macrospins.