Magnetic Recording Medium Hexagonal Ferrite Layer Optimization

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Solution Overview

Problem

Magnetic recording media experience deterioration in electromagnetic conversion characteristics due to spacing loss caused by head attachment and foreign substances, leading to reduced reliability during repeated sliding.

Innovation Solution

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

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an abrasive is added to the magnetic layer to remove head attachment, then the electromagnetic conversion characteristics are improved, but the magnetic layer surface becomes rougher and may cause increased friction

Engineering Contradiction:

Improveelectromagnetic conversion characteristicsVSAvoidfriction and surface roughness

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the particle size distribution of the abrasive within specific ranges (D10: 0.1-0.5 μm, D50: 0.5-2.0 μm, D90: 2.0-5.0 μm) and controls the abrasive content at 0.1-5.0 wt% to balance the head cleaning function with surface smoothness, reducing friction while maintaining electromagnetic conversion characteristics

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite abrasive system combining multiple particle sizes and types (including alumina, silica, or diamond particles) with the magnetic layer matrix, creating a multi-functional layer that provides both head attachment removal and surface smoothing properties

Inventive Principle:

Principle #40Composite materials

2Reliability

If the magnetic layer is made harder to resist scraping, then the reliability during repeated sliding is improved, but the head may experience increased wear

Engineering Contradiction:

Improvedurability during repeated slidingVSAvoidhead wear

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent creates a gradient structure where the abrasive concentration and particle size vary through the magnetic layer thickness, with higher abrasive content near the surface for head protection and softer material deeper in the layer to reduce head wear

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces a lubricant layer or coating between the magnetic layer and the head, using materials like fluorinated compounds or metallic soaps that reduce direct contact friction and prevent both magnetic layer scraping and head wear

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If the surface of the magnetic layer is made smoother to reduce friction, then the head attachment is reduced, but the ability to remove existing head attachment is weakened

Engineering Contradiction:

Improvehead attachmentVSAvoidhead cleaning capability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent designs the magnetic layer with viscoelastic properties that allow it to deform under head contact pressure, exposing abrasive particles for cleaning action, then return to a smoother state when the head moves away, creating a dynamic surface that alternates between smooth and abrasive

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent utilizes the periodic contact and separation of the sliding head to activate the abrasive particles during contact phases for cleaning, while maintaining smoothness during separation phases, creating a cyclic cleaning-smoothing action

Inventive Principle:

Principle #19Periodic action

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 optimized magnetic recording medium effectively prevents deterioration of electromagnetic conversion characteristics during repeated sliding, enhancing the reliability and performance of data storage applications.

Implementation Method 1

the ferromagnetic powder is ferromagnetic hexagonal ferrite powder

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 2

an abrasive has been added to the magnetic layer such that the surface of the magnetic layer performs a function of removing the head attachment

Methodology Applied

Scientific EffectAbrasion: Abrasion

Implementation Method 3

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

Data Source

PatentUS10854227B2Magnetic recording medium having characterized magnetic layer

Publication Date: 2020.12.01 FUJIFILM CORP

AI summary

The magnetic recording medium includes a non-magnetic support and a magnetic layer which contains ferromagnetic powder and a binder, in which the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, the magnetic layer contains an abrasive, Int (110)/Int (114) 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 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, a squareness ratio of the magnetic recording medium in a vertical direction is equal to or higher than 0.65 and equal to or lower than 1.00, and a logarithmic decrement obtained by performing a pendulum viscoelasticity test on a surface of the magnetic layer is equal to or lower than 0.050.