Magnetic Recording Medium Seed Layer Crack Resistance
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Solution Overview
Problem
Magnetic recording media face challenges in maintaining durability and reliability due to crack generation in the laminate film, which degrades their magnetic characteristics and recording capacity, especially when using fine grains with diameters of 10 nm or less.
Innovation Solution
A magnetic recording medium is developed with a flexible substrate, an amorphous seed layer, and an under layer containing Ru, where the seed layer is between the substrate and the under layer, and the under layer thickness is in the range of 5 to 50 nm, enhancing magnetic characteristics and suppressing crack generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a thin film is formed using fine grains having a diameter of 10 nm or less by a currently used coating method, then surface recording density is improved, but the film cannot be formed properly
Solution Approach 1:
The patent changes the deposition parameters by using a sputtering method with specific conditions (power density, gas pressure, substrate temperature) to enable film formation using ultrafine grains of 10 nm or less, which cannot be formed by conventional coating methods
Solution Approach 2:
The patent replaces the conventional coating method with a sputtering method, substituting a mechanical/chemical deposition process with a physical vapor deposition process that can handle ultrafine grains effectively
2Reliability
If the under layer thickness is increased to improve magnetic characteristics, then orientation is improved, but crack generation is promoted
Solution Approach 1:
The patent optimizes the under layer thickness to a specific range (5-50 nm) to achieve the balance between magnetic characteristics and crack resistance, demonstrating that precise parameter control can resolve the contradiction between orientation improvement and crack suppression
Solution Approach 2:
The patent applies partial action by using a thin under layer (5-50 nm) that provides sufficient magnetic orientation function without excessive thickness that would cause crack generation, achieving the minimum effective dose principle
3Productivity
If a laminate film is formed on the substrate to improve magnetic characteristics, then recording capacity is improved, but crack generation degrades durability and reliability
Solution Approach 1:
The patent applies local quality by creating a granular structure within the recording layer where magnetic grains are separated by non-magnetic material, providing different local properties (magnetic regions for recording capacity, non-magnetic regions for crack suppression) within the same layer
Solution Approach 2:
The patent uses composite materials by combining the under layer containing Ru with the recording layer having granular structure, creating a multi-component system where each material contributes specific functions (Ru for orientation, granular structure for both recording capacity and crack resistance)
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 improves magnetic characteristics, increases surface recording density, and enhances the crack-resistant load, ensuring the medium's reliability and performance as a data storage medium.
Implementation Method 1
a film of a CoCrPt-based metal material having a high magnetic anisotropy is formed on a flexible substrate, for example, by a sputtering method
Implementation Method 2
this material is crystallized and oriented in a direction perpendicular to the surface of the substrate
Data Source
AI summary
A magnetic recording medium includes a flexible substrate, an amorphous seed layer, an under layer containing Ru, and a recording layer having a granular structure. The seed layer is provided between the substrate and the under layer. The under layer has a thickness in a range of 5 to 50 nm.