Magnetic Tape Head Positioning Accuracy via Edge Shape Control
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Solution Overview
Problem
Magnetic tapes with ferromagnetic hexagonal ferrite powder having an activation volume equal to or smaller than 1,600 nm3 experience decreased head positioning accuracy in timing-based servo systems due to edge shape shifts from ideal shapes, leading to errors in recording and reproduction.
Innovation Solution
A magnetic tape with a non-magnetic support and a magnetic layer containing ferromagnetic hexagonal ferrite powder, where the XRD intensity ratio is between 0.5 to 4.0 and the vertical direction squareness ratio is 0.65 to 1.00, and the edge shape of the timing-based servo pattern has a difference (L99.9−L0.1) of 180 nm or less, improving head positioning accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If ferromagnetic hexagonal ferrite powder with small activation volume (≤1,600 nm³) is used to increase recording density, then recording capacity is improved, but head positioning accuracy deteriorates due to edge shape shifts
Solution Approach 1:
The patent applies parameter changes by optimizing the particle size distribution of ferromagnetic hexagonal ferrite powder, specifically controlling the activation volume to be ≤1,600 nm³ with a specific cumulative distribution (L99.9−L0.1 ≤ 180 nm). This parameter optimization resolves the contradiction by enabling high recording density while maintaining servo pattern edge integrity and head positioning accuracy through precise control of the magnetic particle characteristics
Solution Approach 2:
The patent applies local quality by differentiating the requirements for different regions of the magnetic tape. The magnetic layer is designed with specific local properties: ferromagnetic hexagonal ferrite powder with controlled particle size distribution for high-density recording in data regions, while maintaining appropriate magnetic properties in servo regions to preserve edge shape accuracy. This localized quality differentiation allows simultaneous achievement of high recording capacity and accurate head positioning
2Quantity of substance
If data track width is narrowed to increase recording density, then recording capacity is improved, but head tracking accuracy deteriorates
Solution Approach 1:
The patent resolves this contradiction through parameter changes in the magnetic particle characteristics. By controlling the activation volume and particle size distribution of ferromagnetic hexagonal ferrite powder, the patent achieves narrow data track widths for high density while maintaining sufficient magnetic signal strength in servo patterns for accurate head tracking. The specific particle size parameters enable both narrow track width and reliable servo signal detection
Solution Approach 2:
The patent applies preliminary action by pre-optimizing the magnetic layer properties before recording. The ferromagnetic hexagonal ferrite powder is selected and processed to have specific activation volume and particle size distribution characteristics that predetermine the magnetic tape's ability to support both narrow data tracks and accurate servo tracking. This preliminary optimization of material properties enables subsequent high-density recording with maintained tracking accuracy
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 solution effectively maintains head positioning accuracy by controlling the XRD intensity ratio and vertical direction squareness ratio, preventing edge shape shifts and enhancing the recording and reproduction processes in timing-based servo systems.
Implementation Method 1
a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support
Implementation Method 2
an intensity ratio (Int(110)/Int(114)) of a peak intensity Int(110) of a diffraction peak of a (110) plane with respect to a peak intensity Int(114) of a diffraction peak of a (114) plane of a hexagonal ferrite crystal structure obtained by an X-ray diffraction analysis
Data Source
AI summary
The magnetic tape includes a non-magnetic support; and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, in which the magnetic layer includes a timing-based servo pattern, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder having an activation volume equal to or smaller than 1,600 nm3, an XRD intensity ratio Int(110)/Int(114) obtained by an X-ray diffraction analysis of the magnetic layer by using an In-Plane method is 0.5 to 4.0, a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00, and an edge shape of the timing-based servo pattern specified by magnetic force microscope observation is a shape in which a difference (L99.9−L0.1) is equal to or smaller than 180 nm, and a magnetic tape device including the magnetic tape.