Magnetic Head Return Path Section With Interposer
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Solution Overview
Problem
Magnetic heads for perpendicular magnetic recording systems face issues with adjacent track erasure due to skew, where signals on adjacent tracks are erased or attenuated during writing, and the configuration of return path sections can lead to magnetic flux leakage and heat-induced protrusion, degrading read and write characteristics.
Innovation Solution
A magnetic head design featuring a write shield with inclined end faces and a first return path section accommodated by an interposer, which connects to the write shield without exposing its end face over a large area, preventing magnetic flux leakage and heat-induced protrusion, and enhancing recording density by preventing adjacent track erasure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a return path section is configured to connect the write shield to the main pole, then magnetic flux can be captured and redirected effectively, but the end face of the return path section may be exposed over a large area in the medium facing surface, causing magnetic flux leakage
Solution Approach 1:
An interposer made of nonmagnetic material is introduced as an intermediary component between the return path section and the medium facing surface. This interposer supports the return path section at a position away from the medium facing surface, preventing the end face of the return path section from being exposed and causing magnetic flux leakage, while still allowing the return path section to effectively capture and redirect magnetic flux.
Solution Approach 2:
The return path section is positioned in the vertical dimension (away from the medium facing surface) rather than being exposed in the horizontal plane. By elevating the return path section using the interposer, the design transitions the potential magnetic flux leakage problem from a two-dimensional surface exposure issue to a three-dimensional spatial arrangement that eliminates the harmful exposure.
2Device complexity
If the return path section is positioned close to the medium facing surface for compact design, then device size is reduced, but heat from the coil can cause the return path section to protrude toward the recording medium, degrading read and write characteristics
Solution Approach 1:
The interposer acts as a thermal and physical barrier between the coil/return path section assembly and the medium facing surface. This nonmagnetic interposer component isolates the return path section from direct heat exposure and prevents heat-induced protrusion toward the recording medium, while still maintaining a compact overall head structure.
Solution Approach 2:
The interposer is positioned in advance to provide protective cushioning against heat-induced expansion. By having this nonmagnetic support structure in place before heating occurs, the design prevents the return path section from protruding toward the recording medium due to thermal expansion, thereby protecting read and write characteristics from degradation.
3Manufacturing precision
If the write shield is designed with inclined end faces to prevent adjacent track erasure, then recording density is improved, but the configuration becomes more complex
Solution Approach 1:
The write shield is designed with asymmetric inclined end faces rather than symmetric flat surfaces. This asymmetric geometry is specifically configured to prevent adjacent track erasure by controlling the magnetic flux distribution, thereby improving recording density while accepting the increased geometric complexity as a necessary design feature.
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 prevents adjacent track erasure and improves recording density by ensuring the write shield can capture and redirect magnetic flux effectively, while maintaining optimal distance and alignment to prevent heat-induced deformation, thus enhancing write and read characteristics.
Implementation Method 1
a coil that produces a magnetic field corresponding to data to be written on the recording medium
Implementation Method 2
a main pole that allows a magnetic flux corresponding to the magnetic field produced by the coil to pass, and produces a write magnetic field for writing the data on the recording medium
Implementation Method 3
a write shield that is made of a magnetic material and has an end face located in the medium facing surface
Data Source
AI summary
A magnetic head includes a coil, a main pole, a shield, a return path section, and an accommodation part that are disposed above the top surface of a substrate. The accommodation part accommodates at least part of the return path section. The return path section lies between the main pole and the top surface of the substrate, and connects the shield and part of the main pole away from a medium facing surface to each other so that a space through which part of the coil passes is defined. The accommodation part includes an interposer interposed between the return path section and the medium facing surface. The interposer has an inclined surface facing toward the return path section. The return path section includes an inclined portion located between part of the coil and the inclined surface and extending along the inclined surface.