Magnetic Recording Medium Nonmagnetic Layer Ion Implantation

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Solution Overview

Problem

Conventional methods for forming separators in magnetic recording media, such as ion implantation, often require large amounts of ions, leading to diffusion and changes in magnetic properties, which can degrade recording and reproducing performance and corrosion resistance.

Innovation Solution

A method involving the formation of a nonmagnetic layer composed of the same element as the magnetic recording layer, with a mask layer to concentrate nonmagnetic elements, allowing controlled ion implantation to create separators without damaging recording tracks or bits, using elements like Cr, Mo, W, or Ta, and maintaining a nonmagnetic layer thickness of 2 nm or less.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a huge amount of ions are implanted to form separators and improve track density, then recording density is improved, but the magnetic properties of recording tracks deteriorate due to ion diffusion

Engineering Contradiction:

Improvetrack densityVSAvoidrecording and reproducing performance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

A nonmagnetic layer made of carbon is introduced as an intermediary between the ion source and the magnetic recording layer. This carbon buffer layer absorbs excess ion flux and prevents direct damage to the magnetic recording layer, allowing separator formation without compromising recording track integrity

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies selective ion implantation to create local nonmagnetic separators between tracks while leaving the recording track areas unaffected. By controlling the ion implantation pattern, nonmagnetic regions are formed only where separators are needed, preserving the magnetic properties of recording tracks

Inventive Principle:

Principle #3Local quality

2Productivity

If ion implantation is used to form separators, then track density is improved, but foreign substances increase on the magnetic film surface

Engineering Contradiction:

Improvetrack densityVSAvoidforeign substances on surface

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The carbon-based nonmagnetic layer serves as a mediator that captures implanted ions before they reach the magnetic recording layer. This prevents foreign substance contamination of the magnetic film surface while still enabling separator formation in the nonmagnetic layer itself

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If ion implantation is used to form separators, then track density is improved, but surface roughness increases

Engineering Contradiction:

Improvetrack densityVSAvoidsurface roughness

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The carbon nonmagnetic layer acts as a buffer that absorbs ion implantation damage, preventing direct modification of the magnetic recording layer surface. This maintains smooth surfaces and enables nano-spacing between the magnetic head and disk

Inventive Principle:

Principle #24Intermediary (Mediator)

4Ease of manufacture

If an ion buffer layer made of different element is used, then separator formation is enabled, but corrosion resistance deteriorates due to different ionization tendencies

Engineering Contradiction:

Improveseparator formation capabilityVSAvoidcorrosion resistance

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent uses carbon as the nonmagnetic layer material, which has uniform ionization characteristics throughout the layer. This homogeneity ensures consistent separator formation and maintains corrosion resistance by avoiding interfaces between different elements with different ionization tendencies

Inventive Principle:

Principle #33Homogeneity

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 approach enhances recording and reproducing performance while maintaining high reliability by precisely controlling the concentration of nonmagnetic elements, improving track density without compromising magnetic properties or corrosion resistance.

Implementation Method 1

a method of forming separators by ion implantation has been attempted

Methodology Applied

Scientific EffectIon implantation: Ion Implantation

Implementation Method 2

a part of the ions may diffuse over the recording tracks to change the magnetic property of the recording tracks

Methodology Applied

Scientific EffectIon diffusion: Diffusion

Data Source

PatentUS8257845B2Magnetic recording medium utilizing a recording layer having more and less concentrated parts of a nonmagnetic element in an in-plane direction and a nonmagnetic layer

Publication Date: 2012.09.04 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

Embodiments of the present invention help to produce discrete track media and bit patterned media having both excellent recording and reproducing performance and reliability. According to one embodiment, a manufacturing method forms a nonmagnetic layer mainly composed of the same element as a nonmagnetic element contained in magnetic recording layers and on the magnetic recording layers and a mask layer having apertures for forming more concentrated parts of the nonmagnetic element in the magnetic recording layers on the nonmagnetic layer. The method implants ions of the nonmagnetic element through the nonmagnetic layer masked by the mask layer to form the more concentrated parts of the nonmagnetic element in the magnetic recording layer.