Magnetic Tape Servo Band Squareness Ratio Optimization
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Solution Overview
Problem
The increasing capacity of magnetic tapes leads to narrower servo band widths, resulting in increased azimuth loss and a decreased signal-to-noise ratio (SNR) of servo reproduction signals, particularly due to the demagnetizing field in perpendicular magnetic recording methods.
Innovation Solution
A magnetic recording medium with a tape-shaped configuration, featuring a magnetic layer with a servo band, where the squareness ratio and the ratio of peak-to-peak magnetic force gradient strengths are optimized to achieve a high signal-to-noise ratio by setting the index Sq×Fact.(p−p)/F0(p−p) to 0.42 or more, using a servo signal recording device with an auxiliary magnetic pole to ensure saturation recording.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the capacity of magnetic tape is increased, then the recording density is improved, but the servo band width becomes narrower causing increased azimuth loss and decreased SNR
Solution Approach 1:
The patent applies parameter changes by optimizing the squareness ratio (Sq) of the magnetic layer to be 0.40 or more, and controlling the index Sq×Fact.(p−p)/F0(p−p) to be 0.42 or more. These parameter optimizations maintain sufficient magnetic moment in the narrowed servo band, thereby preserving servo signal quality despite reduced bandwidth when increasing recording capacity.
2Quantity of substance
If the inclination angle of azimuthal slope is increased to cope with increased capacity, then the recording density is improved, but the azimuth loss increases and SNR decreases
Solution Approach 1:
The patent optimizes the squareness ratio parameter to compensate for the increased azimuth loss. By maintaining Sq≥0.40 and the index Sq×Fact.(p−p)/F0(p−p)≥0.42, the magnetic layer retains sufficient magnetic moment even with larger inclination angles, thereby preserving servo signal quality while enabling higher recording density.
3Quantity of substance
If perpendicular magnetic recording method is used, then the recording density is improved, but the SNR of servo reproduction signal decreases due to demagnetizing field
Solution Approach 1:
The patent addresses the demagnetizing field issue by optimizing the squareness ratio to 0.40 or more and controlling the index Sq×Fact.(p−p)/F0(p−p) to 0.42 or more. These parameter optimizations ensure that the magnetic layer maintains sufficient magnetic moment perpendicular to the tape surface, compensating for the demagnetizing field effects and preserving servo signal quality in perpendicular magnetic recording.
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 effectively suppresses the degradation of servo reproduction signals, maintaining high SNR even with increased tape capacity, by optimizing the magnetic layer's properties and using an auxiliary magnetic pole for saturation recording.
Implementation Method 1
a perpendicular magnetic recording method in which magnetic particles in the magnetic layer are magnetized in a perpendicular direction to record data
Implementation Method 2
The magnetic head performs alignment with respect to the recording tracks by reading servo signals recorded on servo bands
Implementation Method 3
a peak-to-peak value of a first magnetic force gradient strength observed by a magnetic force microscope when a servo signal is saturation-recorded on the magnetic layer
Data Source
AI summary
[Solving Means] A magnetic recording medium according to an embodiment of the present technology is a tape-shaped magnetic recording medium, including: a magnetic layer including a servo band, a servo signal being recorded on the servo band. An index expressed by Sq×Fact.(p−p)/F0(p−p) is 0.42 or more, Sq being a squareness ratio of the magnetic layer in a perpendicular direction, F0(p−p) being a peak-to-peak value of a first magnetic force gradient strength observed by a magnetic force microscope when a servo signal is saturation-recorded on the magnetic layer, Fact.(p−p) being a peak-to-peak value of a second magnetic force gradient strength for the servo signal recorded on the servo band observed by the magnetic force microscope.