Perpendicular Magnetic Recording Medium Tailored Granular Layers
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Solution Overview
Problem
Current perpendicular magnetic recording media face challenges in achieving high recording density due to significant magnetostatic interaction between magnetic crystal grains and larger grain sizes, which affect signal quality and stability.
Innovation Solution
A perpendicular magnetic recording medium is designed with a granular structure where magnetic crystalline materials are surrounded by nonmagnetic amorphous materials, optimizing interface and surface energies to reduce magnetostatic interaction and grain size, featuring multiple layers with specific energy conditions to enhance recording density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic crystal grains are made larger, then signal quality is improved, but magnetostatic interaction between grains increases and recording density decreases
Solution Approach 1:
The magnetic layer is segmented into discrete magnetic crystal grains separated by nonmagnetic amorphous regions. This segmentation isolates magnetic grains, reducing magnetostatic interaction between them while maintaining sufficient grain size for signal quality, thereby enabling higher recording density
Solution Approach 2:
The structure transitions from uniform magnetic material to a composite structure with local variations: magnetic crystal grains in regions where signal quality is needed, and nonmagnetic amorphous material in regions where magnetostatic interaction occurs. This local differentiation resolves the contradiction between grain size and interaction strength
2Productivity
If magnetic crystal grain size is reduced, then recording density is improved, but magnetostatic coupling forces increase
Solution Approach 1:
Nonmagnetic amorphous material acts as an intermediary substance between magnetic crystal grains. This intermediary layer physically separates the grains and provides a nonmagnetic barrier that reduces magnetostatic coupling forces, allowing smaller grain sizes to be used without excessive interaction
Solution Approach 2:
The magnetic layer is constructed as a composite material system combining magnetic crystalline phases with nonmagnetic amorphous phases. This composite structure enables the magnetic grains to be smaller for high density while the nonmagnetic phase reduces coupling forces through its magnetic isolation properties
Data Source
AI summary
A perpendicular magnetic recording medium is disclosed. The perpendicular magnetic recording medium includes a first layer, and a second layer positioned immediately below the first layer. Among the materials in the first layer and the second layer, if the interface energy when two different materials—material a and material b—are in contact is defined as Ei(a//b), the surface energy when material a exists independently is defined as Es(a), and the energy resulting by subtracting the sum of the respective surface energies (ΣEs) from the interface energy is defined as G(a//b), then when G(1//3)<G(1//4) holds, either G(2//4) or G(1//3) is the minimum among G(1//3), G(1//4), G(2//3) and G(2//4), and when G(1//3)<G(1//4) does not hold, G(2//4) is the minimum among G(1//3), G(1//4), G(2//3) and G(2//4).