Magnetic Recording Medium Servo Pattern Control
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Solution Overview
Problem
In magnetic recording media, achieving high head positioning accuracy in servo systems is challenging due to the difficulty in accurately tracking narrow data tracks, leading to potential errors during recording and reproduction.
Innovation Solution
A magnetic recording medium with a magnetic layer containing ferromagnetic powders like hexagonal strontium ferrite and ε-iron oxide, with controlled average particle sizes and magnetic cluster areas, enhances head positioning accuracy by improving the formation and stability of servo patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of the data track is narrowed to increase recording density, then recording capacity is improved, but head positioning accuracy deteriorates
Solution Approach 1:
The patent applies local quality by creating servo patterns with specific magnetic cluster area characteristics (0.2×10^4 nm² or more and less than 5.0×10^4 nm²) in localized regions. This allows the magnetic head to accurately detect position information through magnetic force microscope measurements, improving head positioning accuracy in the servo areas without requiring changes to the overall narrow data track width, thus resolving the contradiction between high recording density and positioning precision
Solution Approach 2:
The patent changes the parameter of magnetic cluster area in the servo pattern to a specific range (0.2×10^4 nm² or more and less than 5.0×10^4 nm²). This parameter optimization enables the servo system to achieve accurate head positioning even when data tracks are narrowed for high-capacity recording, as the controlled magnetic cluster size provides reliable position detection signals
2Manufacturing precision
If ferromagnetic powder with smaller particle size is used to improve magnetic layer properties, then head positioning accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies ferromagnetic powder with average particle size of 5 nm or more and 20 nm or less, optimizing the particle size parameter to achieve the desired magnetic cluster area characteristics. This controlled particle size range enables formation of magnetic clusters with area of 0.2×10^4 nm² or more and less than 5.0×10^4 nm², improving head positioning accuracy while maintaining manufacturability through well-established powder synthesis techniques
Solution Approach 2:
The patent uses composite material structure combining ferromagnetic powder particles (5-20 nm) with binding agents to form the magnetic layer. This composite approach allows the ferromagnetic particles to self-organize into magnetic clusters with controlled areas, achieving precise head positioning through the emergent cluster structure rather than requiring complex direct patterning processes
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 use of hexagonal strontium ferrite and ε-iron oxide powders with specific particle size ranges and controlled magnetic cluster areas improves head positioning accuracy in servo systems, reducing errors and enhancing the reliability of data recording and reproduction.
Implementation Method 1
a magnetic layer including ferromagnetic powder and a binding agent, wherein the ferromagnetic powder is selected from the group consisting of hexagonal strontium ferrite powder and ε-iron oxide powder
Implementation Method 2
an average area Sdc of magnetic clusters of the magnetic recording medium in a DC demagnetization state, measured by a magnetic force microscope
Data Source
AI summary
The magnetic recording medium includes: a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent, wherein the ferromagnetic powder is selected from the group consisting of hexagonal strontium ferrite powder and ε-iron oxide powder, and has an average particle size of 5 nm or more and 20 nm or less, wherein the magnetic layer has a servo pattern, and wherein an average area Sdc of magnetic clusters of the magnetic recording medium in a DC demagnetization state, measured by a magnetic force microscope is 0.2×104 nm2 or more and less than 5.0×104 nm2.