Magnetic Media Platinum Gradient for Areal Density
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Solution Overview
Problem
Increasing the areal density capacity of hard disk drives (HDDs) while maintaining or improving the media signal-to-noise ratio (SNR) and coercivity is challenging, as adding more non-magnetic exchange control layers thickens the magnetic stack, reducing SNR and coercivity, and simply reducing the stack thickness does not result in significant areal density gains.
Innovation Solution
A magnetic recording layer structure with a gradient of platinum content across six magnetic recording sublayers and six non-magnetic exchange control sublayers, where the bottom sublayer has the highest platinum content and the top sublayer has the lowest, optimizing magnetic anisotropy and allowing for reduced thickness of intermediate sublayers, thereby improving SNR and areal density capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If more non-magnetic exchange control layers are added to increase areal density capacity, then the magnetic stack thickness increases, but the signal-to-noise ratio and coercivity decrease
Solution Approach 1:
The patent applies local quality by creating a gradient of platinum content across different sublayers. The bottom magnetic recording sublayer has higher platinum content (19-24 atomic percent) while intermediate sublayers have lower platinum content (12-18 atomic percent). This local variation in composition optimizes magnetic anisotropy in each region, allowing the structure to achieve both high areal density and maintained SNR/coercivity performance.
Solution Approach 2:
The patent changes the platinum content parameter across the layer structure to resolve the contradiction. By varying the platinum concentration from bottom to top sublayers, the magnetic anisotropy is optimized at different positions, enabling the system to achieve improved areal density capacity while maintaining the necessary signal-to-noise ratio and coercivity levels.
2Productivity
If more non-magnetic exchange control layers are added to increase areal density capacity, then the magnetic stack thickness increases, but the coercivity decreases
Solution Approach 1:
The patent applies local quality by creating a gradient of platinum content across different sublayers. The bottom magnetic recording sublayer has higher platinum content (19-24 atomic percent) while intermediate sublayers have lower platinum content (12-18 atomic percent). This local variation in composition optimizes magnetic anisotropy in each region, allowing the structure to achieve both high areal density and maintained SNR/coercivity performance.
Solution Approach 2:
The patent uses composite materials by combining magnetic recording sublayers with non-magnetic exchange control sublayers in an alternating pattern. This composite structure, with six pairs of sublayers, allows the system to achieve high areal density capacity while the specific platinum gradient composition maintains the necessary coercivity levels despite the increased number of layers.
3Reliability
If the magnetic stack thickness is reduced to maintain signal-to-noise ratio, then the areal density capacity does not increase significantly
Solution Approach 1:
The patent applies local quality by creating a gradient of platinum content across different sublayers. The bottom magnetic recording sublayer has higher platinum content (19-24 atomic percent) while intermediate sublayers have lower platinum content (12-18 atomic percent). This local variation in composition optimizes magnetic anisotropy in each region, allowing the structure to achieve both high areal density and maintained SNR/coercivity performance.
Solution Approach 2:
The patent achieves multi-functionality by designing a six-pair alternating structure that simultaneously provides areal density enhancement and maintains SNR/coercivity performance. The gradient platinum composition enables each sublayer to contribute to both capacity and performance requirements, making the structure universally effective for high-density recording applications.
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 platinum gradient in the magnetic recording layer structure enhances the signal-to-noise ratio and areal density capacity by optimizing magnetic anisotropy, allowing for a 0.5 dB SNR gain and a 1.92% figure of merit increase in areal density, while maintaining coercivity and reducing sublayer thickness.
Implementation Method 1
The magnetic recording layer structure includes a gradient of platinum content across the magnetic recording sublayers to produce a magnetic anisotropy, Ku, gradient across the magnetic recording layer structure
Data Source
AI summary
Magnetic media including a magnetic recording layer structure of at least six magnetic recording sublayers and at least six non-magnetic exchange control sublayers in an alternating pattern are provided. The magnetic recording layer structure includes a gradient of platinum content across the magnetic recording sublayers such that a top magnetic recording sublayer has a lowest platinum content and a bottom magnetic recording sublayer has a highest platinum content. In one such case, the magnetic media includes a substrate and the magnetic recording layer structure on the substrate. In another case, a method of fabricating such magnetic media is provided.