ε-Iron Oxide Magnetic Recording Medium for Output and Thermal Stability
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Solution Overview
Problem
Existing tape-like magnetic recording media face challenges in achieving both improved electromagnetic conversion characteristics and high long-term reliability, particularly due to the use of ε-iron oxide magnetic powders which have low mass magnetization and insufficient thermal stability.
Innovation Solution
A magnetic recording medium with a magnetic layer containing ε-iron oxide is designed to have a ratio of residual coercivity to perpendicular coercivity (Hrp/Hc) of 2.0 or less and a saturation magnetization per unit area of 4.5 mA or greater, utilizing a stacked structure with specific thicknesses and materials to enhance dispersibility and thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If ε-iron oxide powders are used in the magnetic layer, then thermal stability is improved, but electromagnetic conversion characteristics deteriorate due to low mass magnetization
Solution Approach 1:
The patent applies parameter changes by precisely controlling the ratio of residual coercivity to perpendicular coercivity (Hrp/Hc) at 2.0 or less, and setting saturation magnetization per unit area (Mst) at 4.5 mA or greater. These parameter optimizations resolve the contradiction by achieving both thermal stability and improved electromagnetic conversion characteristics through coordinated control of magnetic properties rather than relying solely on material composition.
2Power
If the magnetic layer is optimized for electromagnetic conversion characteristics, then signal output improves, but long-term reliability deteriorates due to insufficient thermal stability
Solution Approach 1:
The patent resolves this contradiction by establishing specific parameter ranges: Hrp/Hc ratio of 2.0 or less and Mst of 4.5 mA or greater. These parameter changes enable simultaneous achievement of high signal output and long-term reliability by optimizing the magnetic layer's coercivity and magnetization properties to balance electromagnetic performance with thermal stability.
3Quantity of substance
If miniaturization of magnetic powders is implemented to achieve high-density recording, then recording density improves, but mass magnetization decreases leading to insufficient output
Solution Approach 1:
The patent addresses this contradiction by changing the magnetic parameters rather than relying solely on powder size. By controlling Hrp/Hc at 2.0 or less and Mst at 4.5 mA or greater, the patent achieves high recording density while maintaining sufficient mass magnetization and output through optimized magnetic properties of the powder particles.
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
This configuration improves electromagnetic conversion characteristics and ensures long-term reliability by optimizing the magnetic layer's composition and structure, enhancing output and thermal stability while maintaining high-density recording capabilities.
Implementation Method 1
A ratio (Hrp/Hc) of residual coercivity (Hrp) measured in a perpendicular direction of the magnetic recording medium with use of a pulse magnetic field to perpendicular coercivity (Hc) of the magnetic recording medium is 2.0 or less
Implementation Method 2
The magnetic layer includes magnetic powders including ε-iron oxide
Implementation Method 3
improvement in electromagnetic conversion characteristics
Data Source
AI summary
Provided is a magnetic recording medium that is able to achieve both an improvement in electromagnetic conversion characteristics and ensuring of high long-term reliability. The magnetic recording medium includes a magnetic layer and a base. The magnetic layer includes magnetic powders including ε-iron oxide. A ratio (Hrp/Hc) of residual coercivity (Hrp) measured in a perpendicular direction of the magnetic recording medium with use of a pulse magnetic field to perpendicular coercivity (Hc) of the magnetic recording medium is 2.0 or less. Saturation magnetization (Mst) per unit area of the magnetic recording medium is 4.5 mA or greater.