Carbon Grain Isolation Initiation Layer for Perpendicular Recording Media
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Solution Overview
Problem
High-temperature deposition in perpendicular magnetic recording media leads to increased intergranular exchange coupling, degrading signal-to-noise ratio and limiting areal recording density due to enhanced magnetic anisotropy, necessitating materials or processes that reduce this coupling.
Innovation Solution
A carbon grain isolation initiation layer (GIIL) comprising carbon, a metal, and an oxide is introduced between the substrate and the magnetic recording layer, with a non-ordered structure, to minimize intergranular exchange coupling by controlling carbon concentration and diffusion, thereby optimizing magnetic recording performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-temperature deposition is used to increase magnetic anisotropy, then magnetic anisotropy is improved, but intergranular exchange coupling increases
Solution Approach 1:
A grain isolation initiation layer (GIIL) comprising carbon, a metal, and an oxide is introduced between the substrate and the magnetic recording layer. This intermediary layer reduces intergranular exchange coupling while allowing high-temperature deposition to proceed, thereby enabling increased magnetic anisotropy without the harmful effect of enhanced exchange coupling between grains.
Solution Approach 2:
The GIIL is designed with specific compositional parameters (carbon, metal, and oxide components) and structural parameters (non-ordered structure) that enable it to function as an effective barrier against exchange coupling. By changing the parameters of the interface layer between substrate and recording layer, the patent achieves both high magnetic anisotropy and reduced intergranular coupling.
2Strength
If high-temperature deposition is used to improve magnetic anisotropy, then magnetic anisotropy is improved, but signal-to-noise ratio degrades
Solution Approach 1:
The GIIL acts as a mediator that decouples the relationship between deposition temperature and exchange coupling strength. By introducing this intermediate layer, high-temperature deposition can be performed to achieve high magnetic anisotropy without the detrimental effect of increased exchange coupling, thereby maintaining good signal-to-noise ratio.
3Quantity of substance
If high-temperature deposition is used to increase areal recording density, then areal recording density is improved, but intergranular exchange coupling increases
Solution Approach 1:
The GIIL enables high-temperature deposition processes that are necessary for achieving high areal recording density through improved magnetic anisotropy, while simultaneously preventing the increase in intergranular exchange coupling that would otherwise occur. This allows the system to achieve higher areal recording density without the harmful side effect of enhanced exchange coupling.
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
The GIIL effectively reduces intergranular exchange coupling, enhancing coercivity and maintaining magnetic anisotropy, thereby improving recording performance and areal density while allowing high-temperature deposition without degradation.
Implementation Method 1
Maintaining or lowering the magnetic exchange coupling between the grains can be key in maintaining or improving recording performance
Implementation Method 2
Deposition of PMR films (e.g., recording layers) at high temperatures (e.g., 200 degrees Celsius and above)
Implementation Method 3
CoCrPt (or CoPt) grains embedded within a mixture of oxide segregants
Data Source
AI summary
Perpendicular magnetic recording media including a carbon grain isolation initiation layer for reducing intergranular exchange coupling in the recording layer are provided. In one such case, the media includes a substrate, a plurality of underlayers on the substrate, a grain isolation initiation layer (GIIL) on the plurality of underlayers, the GIIL including C, a metal, and an oxide, and a magnetic recording layer directly on the GIIL and including a non-ordered structure. In another case, a method of fabricating such magnetic media is provided.