Hexagonal Ferrite Magnetic Layer XRD Control

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Solution Overview

Problem

Magnetic recording media experience deterioration in electromagnetic conversion characteristics due to head attachment and spacing loss, leading to reduced reliability during repeated signal reproduction.

Innovation Solution

A magnetic recording medium comprising a non-magnetic support with a magnetic layer containing ferromagnetic hexagonal ferrite powder, an abrasive, and a binder, where the magnetic layer's XRD intensity ratio and squareness ratio are controlled to inhibit head and magnetic layer scraping, thereby maintaining stable electromagnetic conversion characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an abrasive is added to the magnetic layer, then head attachment is removed and electromagnetic conversion characteristics are maintained, but the magnetic layer becomes more prone to scraping and deterioration

Engineering Contradiction:
Improveelectromagnetic conversion characteristicsVSAvoidmagnetic layer integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The invention changes the crystallographic parameters of the hexagonal ferrite by controlling the XRD intensity ratio Int(110)/Int(114) to be 0.5-4.0, which fundamentally alters the particle morphology and surface properties. This parameter change enables the magnetic layer to maintain both the ability to remove head attachment and resistance to scraping, resolving the contradiction between reliability and strength

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite magnetic layer system combining hexagonal ferrite particles with specific crystal structure, binder, and abrasive components. The synergistic interaction between these components allows the layer to simultaneously provide head attachment removal functionality while maintaining structural integrity and resistance to scraping during repeated head sliding

Inventive Principle:
Principle #40Composite materials

2Strength

If the magnetic layer is made harder to resist scraping, then magnetic layer durability improves, but head attachment accumulation increases causing spacing loss

Engineering Contradiction:
Improvemagnetic layer durabilityVSAvoidhead attachment
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

By precisely controlling the XRD intensity ratio Int(110)/Int(114) to 0.5-4.0 and squareness ratio to 0.65-1.00, the invention optimizes the magnetic layer's surface properties and particle orientation. This creates an optimal balance where the layer is hard enough to resist scraping but has sufficient surface characteristics to prevent head attachment accumulation, resolving the contradiction between durability and head attachment resistance

Inventive Principle:
Principle #35Parameter changes

3Duration of action of stationary object

If repeated reproduction is performed, then data storage functionality is maintained, but electromagnetic conversion characteristics deteriorate due to head sliding

Engineering Contradiction:
Improvereproduction cyclesVSAvoidelectromagnetic conversion characteristics
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The invention performs preliminary alignment of hexagonal ferrite particles during manufacturing, controlling their crystal orientation so that the easy axis of magnetization is substantially perpendicular to the magnetic layer surface. This preliminary action ensures that the magnetic layer is pre-configured to withstand repeated head sliding without deterioration, maintaining electromagnetic conversion characteristics throughout the reproduction cycles

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the magnetic anisotropy parameters by controlling the squareness ratio to 0.65-1.00 and XRD intensity ratio to 0.5-4.0, which fundamentally alters how the magnetic layer responds to mechanical stress from head sliding. This parameter change enables the layer to maintain stable electromagnetic conversion characteristics even after repeated reproduction operations

Inventive Principle:
Principle #35Parameter changes

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 controlled XRD intensity ratio and squareness ratio in the magnetic layer prevent head scraping and magnetic layer deterioration, ensuring consistent electromagnetic conversion characteristics even with repeated head sliding, enhancing the medium's reliability for data storage.

Implementation Method 1

the ferromagnetic powder is ferromagnetic hexagonal ferrite powder

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

determined by performing X-ray diffraction analysis on the magnetic layer by using an In-Plane method

Methodology Applied
Scientific EffectX-ray diffraction: X-Ray

Implementation Method 3

peak intensity Int (110) of a diffraction peak of (110) plane of a crystal structure

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentUS10692522B2Magnetic recording medium having characterized magnetic layer and method for manufacturing same
Publication Date: 2020.06.23 FUJIFILM CORP

AI summary

The magnetic recording medium has a non-magnetic support and a magnetic layer which is provided on the support and contains ferromagnetic powder and a binder, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer contains an abrasive, an intensity ratio (Int (110)/Int (114)) of a peak intensity Int (110) of a diffraction peak of (110) plane of a crystal structure of the hexagonal ferrite, determined by performing X-ray diffraction analysis on the magnetic layer by using an In-Plane method, to a peak intensity Int (114) of a diffraction peak of (114) plane of the crystal structure is equal to or higher than 0.5 and equal to or lower than 4.0, and a squareness ratio in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00. The present invention also provides a method for manufacturing the magnetic recording medium.