Magnetic Thin Film Production via Magnetic Field Alignment

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Solution Overview

Problem

Magnetic materials with ε-Fe2O3 crystal structure used in magnetic recording applications have a low residual magnetization due to their insulation properties, limiting their effectiveness in utilizing the unique magnetic characteristics of ε-Fe2O3.

Innovation Solution

A process involving the application of a coating liquid containing epsilon-type iron-oxide-based magnetic particles to a film-formation target, followed by curing under an external magnetic field, which aligns the rod-like magnetic particles to enhance residual magnetization, resulting in a magnetic thin film with improved magnetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional production methods are used to create magnetic materials with ε-Fe2O3 crystal structure, then the material can be produced with insulation properties, but the residual magnetization is limited to approximately 0.5 squareness ratio

Engineering Contradiction:
Improveresidual magnetizationVSAvoidutilization of magnetic characteristics
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The invention applies an external magnetic field during the curing process of the coating liquid to preliminarily orient the magnetic particles before the film is fully formed. This preliminary orientation action during the formation process enables the magnetic particles to be aligned in the easy magnetization direction, thereby improving residual magnetization beyond the conventional 0.5 squareness ratio limitation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the processing parameters by applying an external magnetic field with specific intensity (typically 0.1-10 T) during the curing stage. This parameter change affects the orientation state of magnetic particles, transforming the squareness ratio from the conventional 0.5 to higher values, thus improving residual magnetization while maintaining insulation properties

Inventive Principle:
Principle #35Parameter changes

2Reliability

If magnetic particles are used in conventional coating processes, then the film can be formed, but the magnetic particles remain randomly oriented resulting in low residual magnetization

Engineering Contradiction:
Improveresidual magnetizationVSAvoidparticle orientation control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The external magnetic field is applied during the curing process to preliminarily orient magnetic particles in the easy magnetization direction before the coating is fully set. This preliminary orientation control enables precise alignment of particles, improving both residual magnetization and manufacturing precision of particle orientation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The external magnetic field acts as an intermediary force during the curing process to control and align magnetic particles. This intermediary field enables precise orientation control of particles without requiring mechanical intervention, thereby improving manufacturing precision of particle alignment and subsequent residual magnetization

Inventive Principle:
Principle #24Intermediary (Mediator)

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 process significantly improves the residual magnetization of the magnetic thin film, allowing for better utilization of the ε-Fe2O3 crystal structure's magnetic characteristics, making it more suitable for applications like magnetic recording.

Implementation Method 1

a formation process of letting the coating liquid cured while applying an external magnetic field with a predetermined intensity to the coating liquid applied to the film-formation target, and forming a magnetic thin film

Methodology Applied
Scientific EffectMagnetic field alignment: Magnetic Field

Data Source

PatentEP2447965B1Process for production of magnetic thin film
Publication Date: 2020.01.15 DOWA ELECTRONICS MATERIALS CO LTD
  • EP2447965B1 patent drawingFigure 1
  • EP2447965B1 patent drawingFigure 2
  • EP2447965B1 patent drawingFigure 3

AI summary

The present invention provides a process for production of a magnetic thin film which has insulation properties, serves as a permanent magnet, and has improved residual magnetization in comparison with prior arts, the magnetic thin film, and a magnetic material. When a magnetic thin film 3 is formed, an external magnetic field with a predetermined intensity is applied to a coating liquid containing magnetic particles containing epsilon-type iron-oxide-based compounds which have insulation properties and which serve as a permanent magnet, and the coating liquid is let cured in order to form the magnetic thin film 3. Accordingly, the magnetic particles containing the epsilon-type iron-oxide-based compounds can be fixed while being oriented regularly in a magnetization direction. This realizes the process for production of the magnetic thin film 3 which has insulation properties and which serve as a permanent magnet, the magnetic thin film 3, and a magnetic material 1.