HAMR Recording Medium Structure for Smaller High-Aspect Grains
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Solution Overview
Problem
Existing magnetic recording media face challenges in achieving higher areal density due to limitations in reducing magnetic recording grain sizes, which can be addressed by further minimizing grain sizes and enhancing the aspect ratio.
Innovation Solution
The use of a magnetic recording medium with a substrate, a heat sink layer, an underlayer comprising MgO—TiO, and nucleation layers comprising FePt—Ag—X and FePt—Ag—Y, where X is an oxide and Y is an oxide or nitride, along with a magnetic recording layer, facilitated by sputtering processes using specific deposition gases to form TiN, resulting in smaller grains with a high aspect ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If magnetic recording grain sizes are reduced to increase areal density, then areal density is improved, but manufacturing precision becomes more difficult to achieve
Solution Approach 1:
The patent applies preliminary action by creating specialized nucleation layers with controlled compositions (FePt-Ag-oxide and FePt-Ag-nitride) and specific thicknesses (1-3 nm) before depositing the magnetic recording layer. These pre-formed nucleation layers serve as templates that guide grain formation, enabling precise control over grain size and distribution in the subsequent magnetic recording layer, thus achieving small grain sizes (5-15 nm) with high manufacturing precision
Solution Approach 2:
The patent employs parameter changes by systematically varying the composition parameters of the nucleation layers (different oxide and nitride combinations), their thickness parameters (1-3 nm range), and the deposition conditions. This allows optimization of grain nucleation and growth parameters to achieve target grain sizes while maintaining manufacturing feasibility and precision
2Quantity of substance
If heat sink layer and underlayer structure is added to reduce grain size, then areal density is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing the heat sink layer and underlayer structure to serve multiple functions simultaneously: the heat sink layer provides thermal management for HAMR operations, the underlayer with MgO-TiO and nucleation layers provides both adhesion and grain size control, and the entire structure enables small grain formation while maintaining structural integrity. This multi-functionality reduces the need for additional separate layers, managing complexity while achieving high areal density
Solution Approach 2:
The patent uses composite materials by combining different layers with specific properties: heat sink layer (thermal management), underlayer with MgO-TiO (adhesion and structural support), nucleation layers with FePt-Ag-oxide/nitride (grain nucleation control), and magnetic recording layer (data storage). This composite structure allows each layer to contribute its specific function, achieving small grain sizes and high areal density while managing overall device complexity through functional integration
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves a 17% reduction in grain diameter and a 14.7% increase in aspect ratio, leading to improved magnetic recording performance and increased areal density.
Implementation Method 1
sputtering a first nucleation layer, comprising FePt—Ag—X where X is an oxide, on the underlayer using a N2 deposition gas
Implementation Method 2
N2 from the N2 deposition gas and Ti from the MTO of the underlayer form TiN
Data Source
AI summary
Various apparatuses, systems, methods, and media are disclosed to provide a heat-assisted magnetic recording (HAMR) medium having small recording grain sizes with high aspect ratio. One example magnetic recording medium includes, a substrate, a heat sink layer on the substrate, an underlayer comprising MgO—TiO on the heat sink layer, an interfacial layer comprising TiN on the underlayer, a first nucleation layer on the interfacial layer and comprising FePt—Ag—X, wherein X is an oxide, a second nucleation layer on the first nucleation layer and comprising FePt—Ag—Y, wherein Y is an oxide or a nitride, and a magnetic recording layer on the second nucleation layer. In another example, the TiN is formed as a part of the underlayer rather than in the interfacial layer.