TMR Head Resistance Stability in Magnetic Tape Servo Systems
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Solution Overview
Problem
The use of TMR heads as servo heads in magnetic tape devices experiences a significant decrease in resistance value, leading to decreased sensitivity and signal intensity, which affects the accuracy of head position control during head tracking servo operations.
Innovation Solution
A magnetic tape device with a TMR head using a magnetic tape that includes a non-magnetic support, a magnetic layer with ferromagnetic powder, a binding agent, and fatty acid ester, where the full width at half maximum of spacing distribution before and after vacuum heating, and the difference in spacing measurements, are optimized to prevent resistance value decreases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a TMR head is used as a servo head in a magnetic tape device, then the sensitivity and signal intensity improve, but the resistance value decreases significantly, affecting head position control accuracy
Solution Approach 1:
The patent changes the physical and chemical parameters of the magnetic tape by incorporating fatty acid ester as a lubricant and optimizing the spacing distribution parameters (FWHM before and after vacuum heating, and difference in spacing measurements). These parameter changes create a controlled interaction environment that prevents excessive resistance decrease in the TMR head while maintaining high sensitivity for servo pattern reading.
Solution Approach 2:
The magnetic layer is formulated as a composite material containing ferromagnetic powder, binding agent, and fatty acid ester. This composite structure provides both the magnetic recording properties and the lubricating effect that prevents excessive resistance decrease in the TMR head, resolving the contradiction between sensitivity improvement and resistance stability.
2Quantity of substance
If the recording density is increased to achieve high capacity, then the recording capacity improves, but the magnetic signal becomes weaker
Solution Approach 1:
The patent optimizes the magnetic layer composition parameters, specifically incorporating fatty acid ester and controlling the spacing distribution characteristics. These parameter changes enhance the magnetic signal strength by improving the interaction between the magnetic particles and the TMR head, thereby maintaining high signal strength even at increased recording densities.
3Manufacturing precision
If the width of the data track is narrowed to increase recording density, then the recording density improves, but the head tracking accuracy deteriorates
Solution Approach 1:
The patent introduces and optimizes specific parameters related to spacing distribution (FWHM before vacuum heating, FWHM after vacuum heating, and the difference between them). These parameter changes ensure that the magnetic tape surface maintains appropriate characteristics for head tracking, enabling accurate following of narrow data tracks while achieving high recording density.
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 optimization of the magnetic tape structure and surface properties prevents significant resistance value decreases in TMR heads, maintaining sensitivity and accuracy in head tracking servo operations.
Implementation Method 1
the servo 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 servo pattern reading element
Implementation Method 2
Magnetic recording is used as a method of recording information in a recording medium. In the magnetic recording, information is recorded on a magnetic recording medium as a magnetized pattern.
Data Source
AI summary
The magnetic tape device includes: a magnetic tape; and a servo head, in which the servo head is a TMR head, the magnetic tape includes a non-magnetic support, and a magnetic layer including ferromagnetic powder, a binding agent, and fatty acid ester on the non-magnetic support, the magnetic layer includes a servo pattern, full widths at half maximum of spacing distribution measured by optical interferometry regarding a surface of the magnetic layer before and after performing a vacuum heating with respect to the magnetic tape are greater than 0 nm and equal to or smaller than 7.0 nm, and a difference between a spacing measured by optical interferometry regarding the surface of the magnetic layer after performing the vacuum heating with respect to the magnetic tape and a spacing measured before performing the vacuum heating is greater than 0 nm and equal to or smaller than 9.0 nm.