TMR Head Servo Tracking with Hexagonal Ferrite Tape
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Solution Overview
Problem
Magnetic tape devices face challenges in achieving high recording capacity and accurate head tracking due to the weakness of magnetic signals as recording density increases, leading to decreased Signal-to-Noise-Ratio (SNR) when reading servo patterns, especially with existing magnetic heads.
Innovation Solution
A magnetic tape device utilizing a TMR head with a magnetic layer containing ferromagnetic hexagonal ferrite powder and a binding agent, optimized with specific XRD intensity and vertical direction squareness ratios, to enhance the sensitivity and accuracy of servo pattern reading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If recording density is increased to achieve high capacity, then recording capacity is improved, but magnetic signal strength becomes weak leading to decreased SNR
Solution Approach 1:
The patent changes the magnetic properties of the magnetic layer by using ferromagnetic hexagonal ferrite powder with specific crystal orientation (XRD intensity ratio Int(110)/Int(114) of 0.5 to 4.0) and vertical direction squareness ratio of 0.65 to 1.00. These parameter changes enhance the magnetic signal strength while maintaining high recording density, thereby improving SNR for servo pattern reading.
Solution Approach 2:
The patent uses a composite magnetic layer consisting of ferromagnetic hexagonal ferrite powder particles combined with a binding agent. This composite structure provides both the necessary magnetic properties for high-density recording and enhanced signal strength for accurate servo pattern detection by the TMR head.
2Device complexity
If conventional magnetic heads are used with high recording density, then device complexity is reduced, but head tracking accuracy deteriorates due to weak magnetic signals
Solution Approach 1:
The patent employs a TMR (tunnel magnetoresistance) head which utilizes quantum tunneling effects to achieve high sensitivity. This allows the use of a relatively simple head structure while maintaining high tracking accuracy through the enhanced magnetic signal detection capability provided by the TMR effect and optimized magnetic layer properties.
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 enables reading servo patterns at a high SNR, improving the accuracy of head tracking and maintaining high recording density, thus addressing the limitations of existing technologies.
Implementation Method 1
a magnetic head (a TMR head) including a tunnel magnetoresistance effect type element as a servo pattern reading element
Implementation Method 2
a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the magnetic layer including a servo pattern, the ferromagnetic powder being ferromagnetic hexagonal ferrite powder
Data Source
AI summary
The magnetic tape device includes a magnetic tape and a TMR head (servo head), in which the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder, an intensity ratio 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 of the magnetic layer by using an In-Plane method is 0.5 to 4.0, and a vertical direction squareness ratio of the magnetic tape is 0.65 to 1.00.