Multi-level recording in dual-layer FePt-C granular film for heat-assisted magnetic recording

TL;DR

This paper presents a novel dual-layer FePt-C nanogranular film media enabling multi-level heat-assisted magnetic recording, significantly increasing data storage capacity by exploiting different magnetic properties of each layer.

Contribution

Developed a dual-layer FePt-C nanogranular film with a Ru-C breaking layer, allowing separate magnetic recordings at different levels for multi-level data storage.

Findings

Enabled 3-level magnetic recording in the developed media.

Simulations suggest potential for 4-level recording.

Distinct magnetic properties of layers facilitate multi-level storage.

Abstract

Multi-level magnetic recording is a new concept for increasing the data storage capacity of hard disk drives. However, its implementation has been limited by a lack of suitable media capable of storing information at multiple levels. Herein, we overcome this problem by developing dual FePt-C nanogranular films separated by a Ru-C breaking layer with a cubic crystal structure. The FePt grains in the bottom and top layers of the developed media exhibited different effective magnetocrystalline anisotropies and Curie temperatures. The former is realized by different degrees of ordering in the L10-FePt grains, whereas the latter was attributed to the diffusion of Ru, thereby enabling separate magnetic recordings at each layer under different magnetic fields and temperatures. Furthermore, the magnetic measurements and heat-assisted magnetic recording simulations showed that these media enabled 3-level recording and could potentially be extended to 4-level recording, as the up-down and down-up states exhibited non-zero magnetization.