Magnetic Recording Medium Surface Topography Control
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Solution Overview
Problem
Magnetic recording media using hexagonal strontium ferrite and ε-iron oxide powders in magnetic layers often exhibit deteriorated electromagnetic conversion characteristics due to high anisotropic magnetic fields, which are prone to spacing fluctuations and difficulty in magnetization by recording heads.
Innovation Solution
A magnetic recording medium with a ferromagnetic powder selected from hexagonal strontium ferrite and ε-iron oxide, featuring a standard deviation of magnetic projection height between 0.5 to 2.5 nm, which improves surface roughness and reduces friction, enhancing electromagnetic conversion characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If hexagonal strontium ferrite powder or ε-iron oxide powder is used in the magnetic layer, then high-density recording suitability is improved, but electromagnetic conversion characteristics deteriorate
Solution Approach 1:
The patent changes the surface topography parameter by controlling the standard deviation of magnetic projection height to 2.5 nm or less, which resolves the contradiction between using high-anisotropy materials (for high-density recording) and maintaining good electromagnetic conversion characteristics. This parameter control allows the magnetic head to smoothly follow the surface profile, reducing spacing fluctuations and improving signal-to-noise ratio despite the high anisotropic magnetic field of the ferromagnetic powder.
2Stability of the object's composition
If ferromagnetic powder with high anisotropic magnetic field is used, then thermal stability is improved, but magnetization by recording head becomes difficult
Solution Approach 1:
The patent modifies the surface morphology parameter (standard deviation of magnetic projection height) to enable easier magnetization of high-anisotropy ferromagnetic powder. By ensuring smooth surface topology, the magnetic head can effectively magnetize the particles during the recording process, overcoming the difficulty posed by high anisotropic magnetic fields while preserving thermal stability.
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 specified standard deviation of the magnetic projection height improves electromagnetic conversion characteristics by reducing noise and enhancing the smooth sliding between the magnetic layer and the recording head, thereby improving recording performance.
Implementation Method 1
enhancing the smooth sliding between the magnetic layer and the recording head
Implementation Method 2
exhibiting excellent electromagnetic conversion characteristics
Data Source
AI summary
The magnetic recording medium includes a non-magnetic support, and a magnetic layer including a ferromagnetic powder. The ferromagnetic powder is a ferromagnetic powder selected from the group consisting of a hexagonal strontium ferrite powder and an ε-iron oxide powder. The standard deviation of a height of the magnetic projection portion on a surface of the magnetic layer is in a range of 0.5 to 2.5 nm.