Magnetic Recording Medium Particle Size Optimization
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Solution Overview
Problem
Current magnetic recording media face challenges in achieving high density recording performance and durability due to issues with magnetic layer thickness, surface roughness, and the size and shape of magnetic and non-magnetic powders, leading to inadequate recording density and durability.
Innovation Solution
A magnetic recording medium with a non-magnetic substrate, a non-magnetic layer, and a magnetic layer containing particulate non-magnetic and magnetic powders with specific size and shape characteristics, where the average particle size of the non-magnetic powder and the magnetic layer thickness satisfy the relationship 0.88≦R/D≦2.5, enhancing recording and reproducing performance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of the magnetic layer is reduced to improve high density recording performance, then recording density is improved, but surface roughness increases and durability decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the particle size of non-magnetic powder (0.01-2.0 μm) and its ratio to magnetic powder (5-50 wt%), along with magnetic layer thickness (0.03-0.2 μm), to optimize both recording density and durability. This quantitative parameter optimization resolves the contradiction between thin layer requirements for high density and sufficient durability
Solution Approach 2:
The patent uses composite materials by combining magnetic powder (0.5-5.0 μm) with non-magnetic powder (0.01-2.0 μm) in specific proportions within the magnetic layer. This composite structure provides both the magnetic recording functionality and the surface smoothing effect needed for durability, resolving the contradiction between thin layer and surface quality
2Manufacturing precision
If the particle size of magnetic powder is reduced to improve magnetic characteristics for short wavelength recording, then magnetic characteristics are improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by specifying precise particle size ranges for magnetic powder (0.5-5.0 μm) and non-magnetic powder (0.01-2.0 μm), along with their weight ratios. This standardized parameter specification simplifies manufacturing by providing clear targets while achieving improved magnetic characteristics for short wavelength recording
3Manufacturing precision
If highly sensitive MR heads are used to compensate for weakened leakage flux from thin magnetic layers, then recording sensitivity is improved, but thermal noise increases due to surface unevenness
Solution Approach 1:
The patent uses composite materials by incorporating non-magnetic powder (0.01-2.0 μm) into the magnetic layer with magnetic powder. The non-magnetic particles act as spacers that smooth the layer surface, reducing thermal noise from surface unevenness while allowing MR heads to operate effectively, thus resolving the contradiction between sensitivity and noise
Data Source
AI summary
A magnetic recording medium with excellent high density recording performances and good durability comprising a non-magnetic substrate, a non-magnetic layer containing a non-magnetic powder and a binder formed on the non-magnetic substrate, and a magnetic layer having a thickness of less than 100 nm and containing a substantially particulate non-magnetic powder, a substantially particulate magnetic powder having an average particle size of less than 25 nm, and a binder, wherein an average particle size R of the non-magnetic powder contained in the magnetic layer and a thickness D of the magnetic powder satisfy the following relationship: 0.88≦R/D≦2.5.