Thin Film Magnetic Head Pole Dimension Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In high-density magnetic recording, the challenge lies in controlling the magnetic domain structure of thin film magnetic heads to prevent unintended magnetic flux leaks, which can lead to demagnetization and data loss, especially as recording density increases and saturation magnetic flux density materials are used.
Innovation Solution
A thin film magnetic head design with a magnetic pole layer that includes a track width specifying part with a specific dimensional ratio (D/W ≤ 2.3) and a stacked structure, where the magnetic pole layer is made of alloys like iron cobalt, ensuring proper formation of the shape to stabilize the magnetic domain and prevent magnetic flux leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If an iron cobalt alloy with high saturation magnetic flux density is used as the single-pole head material, then the saturation magnetic flux density is improved, but the magnetostriction becomes large making it difficult to obtain proper soft magnetic characteristic
Solution Approach 1:
The single-pole head is segmented into multiple magnetic layers (first magnetic layer, second magnetic layer, third magnetic layer) with different material compositions and properties. The first magnetic layer uses iron cobalt alloy for high saturation magnetic flux density, while the second and third magnetic layers use other materials with lower magnetostriction to provide soft magnetic characteristics. This segmentation allows each layer to fulfill its specific function without compromising the overall performance.
Solution Approach 2:
The invention employs composite material structure by combining different magnetic materials in the stacked layer configuration. The single-pole head consists of multiple magnetic layers with different compositions (iron cobalt alloy, and other alloys with lower magnetostriction), creating a composite structure that simultaneously achieves high saturation magnetic flux density and proper soft magnetic characteristics.
2Productivity
If a two-layered configuration recording medium with soft magnetic layer and recording magnetic layer is used, then the magnetic flux pulling efficiency is improved, but magnetic flux leakage disturbs recording magnetization and causes unintended erasure
Solution Approach 1:
The single-pole head is segmented into multiple magnetic layers with different functions: the first magnetic layer (iron cobalt alloy) provides high saturation magnetic flux density for efficient flux generation, while the second and third magnetic layers (with lower magnetostriction) act as flux containment layers to prevent leakage. This segmentation allows the system to achieve both high flux pulling efficiency and magnetization stability.
Solution Approach 2:
The second and third magnetic layers serve as intermediary layers between the first magnetic layer (flux source) and the recording medium. These intermediary layers mediate the magnetic flux by containing it within the desired recording track, preventing flux leakage that would otherwise disturb the recording magnetization and cause unintended erasure.
3Device complexity
If the magnetic domain structure of the single-pole head is not controlled, then the device complexity is reduced, but magnetic flux leaks unintentionally disturbing recording magnetization
Solution Approach 1:
The single-pole head is divided into multiple magnetic layers with specific dimensional relationships (thickness ratios between layers). This segmentation creates a structured configuration that naturally controls the magnetic domain structure, preventing flux leakage while maintaining reasonable device complexity through systematic layer design.
Solution Approach 2:
The invention controls the magnetic domain structure by precisely adjusting the dimensional parameters (thicknesses) of the magnetic layers. The thickness ratios between the first, second, and third magnetic layers are optimized to control magnetization distribution and prevent flux leakage, demonstrating that parameter optimization can achieve reliable performance without excessive structural 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 design effectively stabilizes the magnetic domain structure, reducing magnetic flux leaks and maintaining recording magnetization stability, thus preventing unintended data erasure and ensuring reliable high-density recording.
Implementation Method 1
a thin film coil for generating a magnetic flux
Implementation Method 2
a magnetic pole layer for emitting the magnetic flux generated by the thin film coil toward a recording medium
Data Source
AI summary
The present invention provides a thin film magnetic head in which a magnetic domain structure of a magnetic pole layer is controlled and fluctuation in recording magnetization caused by leaked magnetic flux generated by unintentional shift of a magnetic domain wall can be prevented. When a length of a front end portion of a magnetic pole part layer, which specifies a recording track width of a recording medium, is set as D, and a width of an upper edge of a magnetic pole end surface, positioned on a medium outflow side, is set as W, a dimensional ratio D/W of the length D to the width W is set so as to lie within the range of 0<D/W<=2.3. Since magnetic domain stability of the magnetic pole part layer is assured on the basis of the proper formation of the shape of the front end portion, leak of magnetic flux from the front end portion immediately after recording is suppressed. Therefore, occurrence of an inconvenience such as unintended erasure of information caused by the leaked magnetic flux is prevented.