Magnetic Recording Medium Coercivity Control
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Solution Overview
Problem
Magnetic recording media using ε-iron oxide magnetic powder often experience decreased electromagnetic conversion characteristics due to thermal disturbances and magnetization reversal issues, particularly with high coercivity values affecting recording density and signal quality.
Innovation Solution
A tape-shaped magnetic recording medium with a recording layer containing ε-iron oxide particles, where the area ratio of the SFD curve within a specific coercivity range is controlled to minimize low coercivity components, enhancing thermal stability and signal fidelity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ε-iron oxide magnetic powder is used to suppress thermal disturbance, then thermal stability is improved, but electromagnetic conversion characteristic deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the coercivity distribution of ε-iron oxide particles. It sets the area ratio Rlow (coercivity between -500 to 500 Oe) to 5.5% or less and Rhigh (coercivity between -15000 to -10000 Oe and 10000 to 15000 Oe) to 5.5% or less, optimizing the balance between thermal stability and electromagnetic conversion characteristic.
Solution Approach 2:
The patent uses composite materials by combining ε-iron oxide particles with specific coercivity distribution characteristics. This composite approach integrates particles with controlled low-coercivity and high-coercivity components to achieve both thermal stability and good electromagnetic conversion.
2Productivity
If magnetic powder is fine-grained to achieve high recording density, then recording density is improved, but thermal disturbance influence increases
Solution Approach 1:
The patent applies parameter changes by controlling particle size and coercivity distribution simultaneously. It specifies average particle size D50 between 8-24 nm while controlling Rlow ≤ 5.5% and Rhigh ≤ 5.5%, achieving fine-grained high-density recording with enhanced thermal stability through optimized coercivity distribution.
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 solution improves electromagnetic conversion characteristics by reducing magnetization reversal and noise, allowing for higher recording densities and sharper magnetization distributions, even at shorter recording wavelengths.
Implementation Method 1
a magnetic recording medium has a recording layer including an ε-iron oxide particle
Implementation Method 2
an area ratio Rlow(=(Slow/Stotal)×100) of a total area Stotal of an SFD curve of the recording layer in a perpendicular direction and an area Slow of the SFD curve in which a coercivity Hc is in a range from −500 [Oe]≤Hc≤500 [Oe]
Data Source
AI summary
A magnetic recording medium is a tape-shaped magnetic recording medium that has a recording layer including an ε-iron oxide particle. An area ratio Rlow (=(Slow/Stotal)×100) of a total area Stotal of an SFD curve of the recording layer in a perpendicular direction and an area Slow of the SFD curve in which a coercivity Hc is in a range from −500 [Oe]≤Hc≤500 [Oe] is equal to or less than 5.5%.