Magnetic Recording Medium Layer Optimization
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Solution Overview
Problem
Magnetic recording media with non-magnetic and magnetic layers on a non-magnetic support face challenges in achieving excellent electromagnetic conversion characteristics due to issues with surface roughness, interface variation, and void volume, leading to deterioration in performance over time.
Innovation Solution
A magnetic recording medium is designed with a non-magnetic support, a non-magnetic layer containing carbon black, and a magnetic layer with ferromagnetic powder, where the vertical squareness ratio, magnetic layer surface roughness, and interface variation rate are optimized to enhance electromagnetic conversion characteristics, and a back coating layer is included to improve stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-magnetic layer and magnetic layer are formed on a non-magnetic support, then the magnetic recording medium can store data, but surface roughness and interface variation deteriorate electromagnetic conversion characteristics
Solution Approach 1:
The patent applies parameter changes by precisely controlling the thickness of the non-magnetic layer (50-200 nm) and magnetic layer (20-100 nm), optimizing the vertical squareness ratio (0.70-1.00), and limiting surface roughness (Ra ≤ 2.5 nm). These parameter optimizations resolve the contradiction by achieving reliable electromagnetic conversion while maintaining manufacturing precision through controlled deposition parameters and process conditions.
Solution Approach 2:
The patent uses composite materials by combining non-magnetic materials (such as Al2O3, SiO2, or carbon black) with ferromagnetic materials (such as γ-Fe2O3, magnetite, or maghemite) in a layered structure. This composite approach allows the non-magnetic layer to provide structural stability and control interface properties, while the magnetic layer provides recording functionality, thereby achieving both reliability and manufacturing precision simultaneously.
2Stability of the object's composition
If the non-magnetic layer thickness is increased to improve stability, then interface variation increases and electromagnetic conversion characteristics deteriorate
Solution Approach 1:
The patent resolves this contradiction through parameter optimization by establishing a specific thickness range for the non-magnetic layer (50-200 nm). This optimized parameter range provides sufficient structural stability and interface control without excessive thickness that would cause interface variation and deteriorate electromagnetic conversion characteristics. The magnetic layer thickness is also optimized (20-100 nm) to maintain both stability and performance.
3Reliability
If surface roughness is reduced to improve electromagnetic conversion characteristics, then manufacturing complexity increases
Solution Approach 1:
The patent addresses this contradiction by optimizing deposition parameters and process conditions to achieve Ra ≤ 2.5 nm surface roughness. By controlling parameters such as deposition rate, substrate temperature, and layer thickness during the formation of non-magnetic and magnetic layers, the patent achieves smooth surfaces that improve electromagnetic conversion characteristics while managing manufacturing complexity through parameter optimization rather than adding complex post-processing steps.
Data Source
AI summary
The magnetic recording medium includes: a non-magnetic support; and a non-magnetic layer including a non-magnetic powder and a magnetic layer including a ferromagnetic powder on the non-magnetic support in this order, in which a vertical squareness ratio is 0.70 to 1.00, a center line average roughness Ra measured regarding a surface of the magnetic layer with an atomic force microscope is equal to or smaller than 2.5 nm, and an interface variation rate between the magnetic layer and the non-magnetic layer in a cross section image obtained by imaging with a scanning electron microscope is equal to or less than 2.5%.