Magnetic Recording Medium with Segmented Tracks for Density

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Solution Overview

Problem

Magnetic recording media face challenges in achieving high recording density due to signal interference between adjacent tracks, instability in head floating characteristics, and contamination issues during surface smoothing processes, which affect signal-to-noise ratio and bit error rate.

Innovation Solution

A magnetic recording medium with a magnetic pattern comprising magnetic regions and non-magnetic regions forming depressions, where the areal ratio difference between data and servo information areas is controlled within 10%, and the depressions have a depth of 0.1 nm to 15 nm, ensuring stable head floating and reduced signal interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If track density is increased to enhance areal recording density, then recording capacity is improved, but magnetic recording information interferes with adjacent tracks and SNR deteriorates

Engineering Contradiction:

Improveareal recording densityVSAvoidsignal interference between adjacent tracks

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The magnetic recording medium is divided into discrete tracks separated by non-magnetic regions. Each track is physically segmented from adjacent tracks by these non-magnetic regions, preventing magnetic signal interference between tracks while maintaining high track density for enhanced areal recording density.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Non-magnetic regions are strategically placed between magnetic recording tracks to create localized magnetic isolation. This local modification of magnetic properties prevents signal interference in critical areas while preserving recording capabilities in the magnetic track regions.

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If bit size is reduced to enhance areal recording density, then recording capacity is improved, but magnetization reversal caused by heat fluctuation increases

Engineering Contradiction:

Improveareal recording densityVSAvoidmagnetization stability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The invention optimizes the size and dimensions of the non-magnetic regions between tracks. By carefully controlling the width and magnetic property strength of these non-magnetic regions, the patent achieves effective magnetic isolation that prevents heat-induced magnetization reversal in small-sized recording bits while maintaining high areal recording density.

Inventive Principle:

Principle #35Parameter changes

3Object-affected harmful factors

If operation is adopted wherein recording is carried out widely but reproduction is carried out narrowly, then influence of adjacent tracks is minimized, but reproduction output becomes rather low

Engineering Contradiction:

Improveinfluence of adjacent tracksVSAvoidreproduction output

Core Design Contradiction:

Object-affected harmful factorsVSPower

Solution Approach 1:

The discrete track structure with non-magnetic regions provides physical segmentation that naturally limits the influence of adjacent tracks during both recording and reproduction operations. This eliminates the need to operate narrowly during reproduction, allowing the use of wider head elements that can achieve higher reproduction output without suffering from adjacent track interference.

Inventive Principle:

Principle #1Segmentation

4Quantity of substance

If elevations and depressions are formed to partition tracks and enhance track density, then areal recording density is improved, but head floating characteristics become unstable

Engineering Contradiction:

Improvetrack densityVSAvoidhead floating characteristics

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The non-magnetic regions are designed with specific dimensional parameters and magnetic properties that provide magnetic isolation without creating significant surface topography variations. This local modification approach enhances track density while maintaining relatively smooth surface characteristics that preserve stable head floating characteristics.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8120869B2Magnetic recording medium and magnetic recording/reproducing apparatus

Publication Date: 2012.02.21 RESONAC HARD DISK CORP

AI summary

A magnetic recording medium having a magnetic pattern magnetically partitioning a magnetic layer, formed on a non-magnetic substrate, wherein the magnetic pattern is comprised of magnetic regions and non-magnetic regions surrounding each of the magnetic regions, the non-magnetic regions form depressions, the magnetic pattern comprises data areas and servo information areas, and the difference between the areal ratio of the depressions in the data areas and the areal ratio thereof in the servo information areas is within ±10%. The magnetic areas preferably comprise a magnetic layer having a granular structure comprised of magnetic grains each surrounded by an oxide, or a two-layer structure comprising the granular structure and a non-granular structure formed on the granular structure. The magnetic recording medium exhibits stable head-floating characteristics, and thus, the largest floating height can be reduced, and a high recording density can be obtained.