TMR Head and Hexagonal Ferrite Tape for High SNR
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Solution Overview
Problem
Magnetic tape devices face challenges in achieving high Signal-to-Noise-Ratio (SNR) due to the weak magnetic signals generated at high recording densities, which is exacerbated by the limited sensitivity of existing reproducing heads used in magnetic tape devices.
Innovation Solution
A magnetic tape device incorporating a TMR head with a magnetic layer containing ferromagnetic hexagonal ferrite powder and a binding agent, where the XRD intensity ratio and vertical direction squareness ratio are optimized to enhance the sensitivity and alignment of magnetic particles, allowing for improved signal detection and reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If recording density is increased to achieve high capacity, then recording capacity is improved, but magnetic signal strength decreases and SNR deteriorates
Solution Approach 1:
The patent changes the material parameters of the magnetic layer by using ferromagnetic hexagonal ferrite powder with specific crystallographic orientation (XRD intensity ratio Int(110)/Int(114) between 0.5 to 4.0) and vertical direction squareness ratio between 0.65 to 1.00. These parameter changes enhance the magnetic signal strength while maintaining high recording density, thereby improving SNR without sacrificing recording capacity.
Solution Approach 2:
The patent employs a composite magnetic layer structure combining ferromagnetic hexagonal ferrite powder particles with a binding agent. This composite material approach allows optimization of both magnetic properties (for strong signal) and physical properties (for high density recording), resolving the contradiction between recording capacity and signal strength.
2Device complexity
If conventional reproducing heads are used in magnetic tape devices, then device simplicity is maintained, but sensitivity is insufficient for high-density recording
Solution Approach 1:
The patent utilizes the tunnel magnetoresistance (TMR) effect, a quantum mechanical parameter change phenomenon, to achieve high sensitivity in the reproducing head. The TMR head detects magnetic signals through resistance changes in a tunnel junction structure, providing the enhanced sensitivity needed for high-density magnetic tape recording while maintaining reasonable device complexity.
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 optimized magnetic tape device achieves high SNR and enables the reproduction of information recorded at high densities, effectively addressing the limitations of existing technologies by enhancing the sensitivity and alignment of magnetic particles.
Implementation Method 1
a reproducing head, in which the reproducing head is a magnetic head (hereinafter, also referred to as a 'TMR head') including a tunnel magnetoresistance effect type element (hereinafter, also referred to as a 'TMR element') as a reproducing element
Implementation Method 2
the magnetic layer including ferromagnetic powder and a binding agent on the non-magnetic support, the ferromagnetic powder is ferromagnetic hexagonal ferrite powder
Data Source
AI summary
The magnetic tape device includes a magnetic tape and a TMR 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.