L10 Magnetic Recording Medium Underlayer Design
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Solution Overview
Problem
Existing magnetic recording media face challenges in achieving high recording density and reliability due to peeling issues and insufficient anticorrosion properties when using certain underlayer configurations, which affect the coercivity and signal-to-noise ratio (SNR).
Innovation Solution
A magnetic recording medium is designed with a substrate, a magnetic layer having an L10 type crystal structure, and multiple underlayers, including a first underlayer with Ta, Nb, Ti, and V elements, and a second underlayer of MgO, which are consecutively stacked to improve grain dispersion and reduce peeling stress, enhancing the medium's anticorrosion properties and SNR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a magnetic recording medium uses a simple underlayer configuration, then the device complexity is reduced, but peeling stress occurs and anticorrosion properties deteriorate
Solution Approach 1:
The underlayer is divided into multiple distinct layers (first underlayer, second underlayer, third underlayer) with different material compositions and functions. Each layer addresses specific requirements: the first underlayer controls grain size, the second underlayer provides anticorrosion protection, and the third underlayer manages stress, thereby resolving the contradiction between simplicity and reliability through functional segmentation.
Solution Approach 2:
The patent employs composite material structures in the underlayer configuration, combining different materials (e.g., Ru, Rh, Ir, Os, Pt, Pd) in specific layers. This composite approach enables each layer to contribute its unique properties, achieving both low peeling stress and high anticorrosion properties without requiring a single complex material system.
2Productivity
If the magnetic grain diameter is reduced to increase recording density, then the storage capacity increases, but thermal stability deteriorates
Solution Approach 1:
The patent changes the physical and chemical parameters of the underlayer materials and their thicknesses to optimize the magnetic grain characteristics. By adjusting parameters such as the composition of the first underlayer (affecting grain diameter) and the second underlayer (affecting thermal stability), the system achieves both high recording density and thermal stability through parameter optimization rather than simply scaling dimensions.
Solution Approach 2:
The underlayer acts as an intermediary between the substrate and the magnetic layer, mediating the relationship between grain size and thermal stability. The first underlayer controls grain nucleation and size, while the second underlayer provides thermal stability, allowing the magnetic layer to achieve high recording density without sacrificing thermal stability through this intermediary control mechanism.
3Ease of manufacture
If a single-layer underlayer is used, then the manufacturing process is simplified, but grain dispersion and peeling stress control are insufficient
Solution Approach 1:
The underlayer is segmented into multiple functional layers, each responsible for specific manufacturing precision requirements. The first underlayer controls grain dispersion, the second underlayer manages peeling stress, and the third underlayer provides additional stability. This segmentation allows each layer to be optimized for its specific function while maintaining a relatively simple overall manufacturing process.
Solution Approach 2:
The multi-layer underlayer structure provides multi-functionality, where each layer serves multiple purposes: the first underlayer both controls grain dispersion and provides a template for subsequent layers, the second underlayer provides both stress control and anticorrosion protection, and the third underlayer adds both mechanical stability and chemical resistance. This multi-functionality achieves high manufacturing precision without proportionally increasing process complexity.
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 proposed configuration improves the coercivity, SNR, and anticorrosion properties of the magnetic recording medium, reducing peeling stress and maintaining thermal stability, thereby enhancing the reliability and recording density.
Implementation Method 1
The orientation of the L10 type ordered alloy can be controlled by the underlayer, and thus, the orientation of the magnetic layer can be controlled by use of a suitable underlayer
Implementation Method 2
a magnetic material having a high crystal magnetic anisotropy constant Ku
Implementation Method 3
The heat-assisted recording method performs recording with respect to a magnetic recording medium using a magnetic head mounted with a laser light source, by heating the magnetic recording medium by the magnetic head
Implementation Method 4
The microwave-assisted recording method can perform the recording with respect to the magnetic recording medium with a recording magnetic field lower than or equal to the coercivity of the magnetic recording medium, by the assistance of a high-frequency magnetic field generated from the magnetic head
Data Source
AI summary
A magnetic recording medium includes a substrate, a magnetic layer including an alloy having a L10 type crystal structure as a main component thereof, and a plurality of underlayers arranged between the substrate and the magnetic layer. The plurality of underlayers include a first underlayer including two or more elements selected from a group consisting of Ta, Nb, Ti, and V, and one or more elements selected from a group consisting of W and Mo, and a second underlayer including MgO.