Thin Film Magnetic Head Thermal Protrusion Suppression
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Solution Overview
Problem
Existing thin film magnetic heads face challenges in suppressing thermal protrusion due to limitations in heat radiation and thermal expansion suppression methods, which can lead to reduced reliability and effectiveness in magnetic data storage.
Innovation Solution
A thin film magnetic head design incorporating a main magnetic pole layer, first and second return yoke layers, and a thermal expansion suppression layer, where the second return yoke layer fills the recess of the first return yoke layer, allowing for a flat surface for the thermal expansion suppression layer, reducing the risk of cracks and mask layer residues, and enhancing heat radiation by transferring heat to the thermal expansion suppression layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a larger write current is flown to generate a strong write magnetic field, then the write capability is improved, but the thin film magnetic head is heated causing thermal protrusion which worsens reliability
Solution Approach 1:
A thermal expansion suppression layer is introduced as an intermediary component between the magnetic head components and the substrate. This layer acts as a mediator that compensates for thermal expansion differences, allowing strong write currents to be used while preventing thermal protrusion that would otherwise occur due to differential expansion between materials
Solution Approach 2:
The thermal expansion suppression layer changes the thermal expansion parameters of the head structure by using a material with a thermal expansion coefficient matched to the magnetic head components. This parameter matching allows the head to maintain dimensional stability even when subjected to the heating effects of large write currents
2Temperature
If a radiation layer including metal is provided on a magnetic layer to improve heat radiation, then heat radiation is improved, but thermal protrusion may occur under the influence of surrounding temperature environment due to large thermal expansion coefficient of metal
Solution Approach 1:
The invention changes the thermal expansion parameter by selecting a material for the thermal expansion suppression layer whose thermal expansion coefficient is substantially equal to that of the magnetic head components. This parameter matching prevents the thermal protrusion problem that occurs when metal radiation layers with large thermal expansion coefficients are used
Solution Approach 2:
The thermal expansion suppression layer uses a composite material structure that provides both thermal management and dimensional stability. Rather than using simple metal radiation layers, the invention employs a multi-layer composite structure where the thermal expansion suppression layer is specifically designed to match the thermal expansion characteristics of the magnetic head
3Reliability
If a thermal expansion suppression layer is provided directly on the magnetic layer to suppress displacement, then thermal protrusion is suppressed, but cracks or mask layer residues may occur in recess portions
Solution Approach 1:
The invention applies preliminary action by forming a flat surface on the thermal expansion suppression layer before subsequent processing steps. This preliminary flat surface preparation prevents the formation of recesses that would later cause cracking or mask layer residue problems, ensuring both thermal protrusion suppression and manufacturing quality
Solution Approach 2:
The thermal expansion suppression layer is designed with specific local properties - it provides thermal expansion compensation where needed while maintaining a flat surface topology in areas where subsequent processing will occur. This local differentiation of function allows simultaneous achievement of thermal protrusion suppression and prevention of manufacturing defects
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
This design effectively suppresses thermal protrusion while maintaining the reliability and write characteristics of the thin film magnetic head, ensuring stable magnetic spacing and efficient heat dissipation.
Implementation Method 1
thermal expansion suppression layer including a material, which has a small thermal expansion coefficient and a large heat conductivity
Implementation Method 2
improve heat radiation
Data Source
AI summary
A thin film magnetic head is provided, in which thermal protrusion can be suppressed. The thin film magnetic head includes a main magnetic pole layer which conducts a magnetic flux into the recording medium so that the recording medium is magnetized in a direction perpendicular to a surface of the recording medium, a first return yoke layer provided in a trailing side of the main magnetic pole layer, and has a recess in a top surface, a second return yoke layer provided so as to fill at least the recess of the first return yoke layer, and a thermal expansion suppression layer provided in a trailing side of the second return yoke layer. Thus, since the thermal expansion suppression layer can be provided on a surface having no recess, a possibility of a crack in the thermal expansion suppression layer can be eliminated.