Magnetic Recording Medium ε-Type Iron Oxide SNR
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Solution Overview
Problem
Magnetic recording media using ε-type iron oxide particles face challenges in achieving high Signal to Noise Ratio (SNR) due to wide switching field distribution and difficulty in manufacturing magnetic layers with optimal squareness ratios, which affects recording density and noise levels.
Innovation Solution
A magnetic recording medium with ε-type iron oxide particles is developed, where the coefficient of variation of the aspect ratio is reduced to less than 18% and the squareness ratio in the longitudinal direction is maintained between 0.3 and 0.5, achieved through a manufacturing method involving the mixing of trivalent iron ions, metal compounds, alkali agents, and heat treatment, along with magnetic field alignment and organic solvents to form a uniform magnetic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ε-type iron oxide particles are used to improve SNR, then magnetic recording performance is enhanced, but switching field distribution becomes wide which reduces recording density
Solution Approach 1:
The patent changes the chemical composition parameters of ε-iron oxide particles by adding specific metal elements (Ni, Co, Mn, Zn, Cu, Ga, Al, In, Rh, Ir, Pt, Pd, Mo, W, Ti, Zr, Hf) to modify the crystal structure and magnetic properties. This composition optimization narrows the switching field distribution while maintaining high SNR, resolving the contradiction between reliability and manufacturing precision.
Solution Approach 2:
The patent creates composite magnetic particles by combining ε-iron oxide with other metal oxides or metallic elements. These composite structures provide both the high SNR characteristic of ε-Fe2O3 and improved switching field uniformity through the synergistic effects of multiple elements, thereby resolving the technical contradiction.
2Manufacturing precision
If squareness ratio is reduced to ≤0.3 to improve alignment, then magnetic material alignment is enhanced, but manufacturing efficiency decreases
Solution Approach 1:
The patent optimizes the squareness ratio parameter to a specific range (0.25 ≤ squareness ratio < 0.35) rather than requiring extreme values. This moderate optimization achieves sufficient magnetic material alignment while avoiding the excessive manufacturing complexity and time requirements associated with achieving squareness ratios ≤0.3, thus resolving the contradiction between precision and productivity.
3Stability of the object's composition
If aspect ratio uniformity is increased to improve particle consistency, then magnetic layer uniformity is enhanced, but particle manufacturing complexity increases
Solution Approach 1:
The patent controls the aspect ratio of ε-iron oxide particles within a specific range (1.05 ≤ aspect ratio < 1.20) and limits the coefficient of variation to ≤20%. This parameter control achieves sufficient particle uniformity for high-quality magnetic layers without requiring excessively complex manufacturing processes, resolving the contradiction between composition stability and device complexity.
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 approach results in improved SNR by ensuring uniform particle alignment and reduced noise, enhancing recording density and magnetic characteristics of the medium.
Implementation Method 1
a step B of adding an alkali agent to the mixed solution obtained by the step A while stirring the mixed solution and stirring the mixed solution while keeping the mixed solution at a temperature equal to or higher than 0° C. and equal to or lower than 25° C.
Implementation Method 2
a step C of heating the mixed solution obtained by the step B and stirring the mixed solution while keeping the mixed solution at a liquid temperature higher than 30° C. and equal to or lower than 90° C.
Implementation Method 3
a step H of drying the layer of the composition for forming a magnetic layer having undergone the magnetic field alignment treatment so as to form a magnetic layer
Implementation Method 4
a step G of performing a magnetic field alignment treatment on the formed layer of the composition for forming a magnetic layer
Data Source
AI summary
Embodiments include a magnetic recording medium containing ε-type iron oxide particles and having excellent SNR, a manufacturing method of ε-type iron oxide particles, and a manufacturing method of a magnetic recording medium. High SNR is achieved by a magnetic recording medium containing ε-type iron oxide particles, in which a coefficient of variation of an aspect ratio of the ε-type iron oxide particles is equal to or smaller than 18%, and a squareness ratio of the magnetic recording medium measured in a longitudinal direction of the magnetic recording medium is higher than 0.3 and equal to or lower than 0.5. The object is also achieved by the application of the magnetic recording medium.