Zero-dc-field rotation-direction-dependent magnetization switching induced by a circularly polarized microwave magnetic field

Hirofumi Suto,Taro Kanao,Koichi Mizushima,Tazumi Nagasawa,Rie Sato

doi:10.1038/s41598-017-13770-w

Abstract

Magnetization switching of high-anisotropy nanomagnets by a small magnetic field is a key challenge in developing future magnetic nanodevices. In this paper, we experimentally demonstrate magnetization switching of a perpendicularly magnetized nanomagnet induced solely by an in-plane circularly polarized microwave magnetic field. Applying a microwave field with an amplitude below 5% of the anisotropy field induces large ferromagnetic resonance excitation, which results in magnetization switching even in the absence of a dc field. This kind of magnetization switching is induced by a microwave field with a duration of 0.5 ns and is clearly dependent on the rotation direction of the microwave field.

Highlights

Magnetization switching of nanomagnets is a core technology in magnetic recording
The principle behind this switching method is large ferromagnetic resonance (FMR) excitation, which results in magnetization switching without a perpendicular dc magnetic field
Because FMR excitation is a precessional motion of the magnetization that rotates in the right-hand screw direction about the equilibrium direction, FMR excitation and subsequent switching occurs only when the microwave field rotates in the same direction

Summary

Introduction

Magnetization switching of nanomagnets is a core technology in magnetic recording. Conventionally, applying a magnetic field larger than the switching field can reverse the magnetization direction. We first study magnetization switching of the 50-nm nanomagnet by applying a circularly polarized microwave field that rotates clockwise (CW) in the x–y plane.

Results

Conclusion