Micromagnetic Simulation of L10-FePt-Based Exchange-Coupled-Composite-Bit-Patterned Media with Microwave-Assisted Magnetic Recording at Ultrahigh Areal Density.

Pirat Khunkitti,Anan Kruesubthaworn,Apirat Siritaratiwat,Naruemon Wannawong,Chavakon Jongjaihan,Arkom Kaewrawang

doi:10.3390/mi12101264

Pirat Khunkitti, Anan Kruesubthaworn + Show 4 more

Open Access

PDF Available

https://doi.org/10.3390/mi12101264

Copy DOI

Export

Save

Cite

Journal: Micromachines	Publication Date: Oct 17, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: Khon Kaen University

Abstract
Highlights/Summary
Full-Text PDF
Similar Papers

Abstract

Listen

In this work, we propose exchange-coupled-composite-bit-patterned media (ECC-BPM) with microwave-assisted magnetic recording (MAMR) to improve the writability of the magnetic media at a 4 Tb/in2 recording density. The suitable values of the applied microwave field’s frequency and the exchange coupling between magnetic dots, Adot, of the proposed media were evaluated. It was found that the magnitude of the switching field, Hsw, of the bilayer ECC-BPM is significantly lower than that of a conventional BPM. Additionally, using the MAMR enables further reduction of Hsw of the ECC-BPM. The suitable frequency of the applied microwave field for the proposed media is 5 GHz. The dependence of Adot on the Hsw was additionally examined, showing that the Adot of 0.14 pJ/m is the most suitable value for the proposed bilayer ECC-BPM. The physical explanation of the Hsw of the media under a variation of MAMR and Adot was given. Hysteresis loops and the magnetic domain of the media were characterized to provide further details on the results. The lowest Hsw found in our proposed media is 12.2 kOe, achieved by the bilayer ECC-BPM with an Adot of 0.14 pJ/m using a 5 GHz MAMR.

Highlights

The capacity of hard disk drives has been heading towards a stalemate since the thermal stability of the conventional media has reached its limitation [1,2,3,4,5,6]
Without microwave-assisted magnetic recording (MAMR), the media with an Adot of 0.14 pJ/m have the variation of Adot under the MAMR indicates a similar trend of Hsw for all f ac
The lowest Hsw found in this work is 12.2 kOe, achieved by the proposed bilayer exchange-coupled-composite-bit-patterned media (ECC-bit-patterned media (BPM)) with an Adot of 0.14 pJ/m using a 5 GHz MAMR, which is below the maximum write head field existed in the literature

Summary

Introduction

The capacity of hard disk drives has been heading towards a stalemate since the thermal stability of the conventional media has reached its limitation [1,2,3,4,5,6]. In order to increase recording densities, several techniques have been proposed to overcome the stability limitation, such as exchange-coupled-composite (ECC) media, heat-assisted magnetic recording (HAMR) bit-patterned media (BPM), and microwave-assisted magnetic recording (MAMR) [1,7,8,9,10,11,12,13,14]. The interface exchange coupling between two layers can provide a lower Hsw than the conventional one It enables the use of smaller media grain sizes with higher magnetic anisotropy, Ku , at high areal densities [7]. Microwaveassisted magnetic recording (MAMR) is one promising technology for achieving higher areal densities [14,15,16,17,18] The goal of this technique is to reduce the Hsw of the media by using an AC-magnetic field, Hac , operated at a microwave range. The object-oriented micromagnetic framework (OOMMF) software [20] was used in the simulations implementing the Landau–Lifshitz–Gilbert (LLG) equation

Modeling and Analytical Methodology

Results and Discussions

Conclusions