Dual-structure microwave-assisted magnetic recording using only a spin torque oscillator

Simon John Greaves,Waka Saito

doi:10.1063/1.5129724

Abstract

The selective switching of dual-structure magnetic dots under the influence of the stray field from a spin torque oscillator was investigated. A configuration was found which allowed selective switching of either structure when subject to ac magnetic fields oscillating at 9 GHz and 20 GHz. No other external magnetic fields were needed to switch the magnetisation of the structures.

Highlights

INTRODUCTIONMicrowave-assisted magnetic recording (MAMR) makes use of high frequency (HF) magnetic fields which, when oscillating at, or near, the resonance frequency of a magnetic material, reduce the switching field of the magnetic material. When the HF field is applied in conjunction with the field from a write head magnetic grains with much higher uniaxial anisotropy, Ku, can be switched than when using the head field alone
When the high frequency (HF) field is applied in conjunction with the field from a write head magnetic grains with much higher uniaxial anisotropy, Ku, can be switched than when using the head field alone
The sense of rotation of the HF field, or chirality, determines the direction of magnetisation switching, e.g., from up to down, or vice-versa,7 and this can be controlled by the direction in which the current flows through the device

Summary

INTRODUCTION

Microwave-assisted magnetic recording (MAMR) makes use of high frequency (HF) magnetic fields which, when oscillating at, or near, the resonance frequency of a magnetic material, reduce the switching field of the magnetic material. When the HF field is applied in conjunction with the field from a write head magnetic grains with much higher uniaxial anisotropy, Ku, can be switched than when using the head field alone. In some cases it is possible to switch the magnetisation of a recording medium or magnetic dot using only the field from the STO and with no other external field sources.. The sense of rotation of the HF field, or chirality, determines the direction of magnetisation switching, e.g., from up to down, or vice-versa, and this can be controlled by the direction in which the current flows through the device.. The sense of rotation of the HF field, or chirality, determines the direction of magnetisation switching, e.g., from up to down, or vice-versa, and this can be controlled by the direction in which the current flows through the device.8 Another advantage of MAMR is the ability to record on media or dots with multiple recording structures.. No write head or any other external applied fields were used

THE MODEL

CONCLUSIONS