Perpendicular Magnetic Recording Head Stepped Return Path
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Solution Overview
Problem
Perpendicular magnetic recording heads face challenges in simultaneously enhancing the intensity and gradient of the recording magnetic field due to the limitations in the design of the main magnetic pole and return path layers, where increasing one parameter typically decreases the other.
Innovation Solution
The design incorporates stepped portions on the main magnetic pole and return path layers, with a larger gap at the rear in the height direction and a smaller gap near the recording medium, allowing for a two-step throat structure that maintains magnetic flux intensity while improving the gradient of the recording magnetic field.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the throat height is small, then the intensity of the recording magnetic field increases, but the gradient of the magnetic field cannot be sufficiently increased
Solution Approach 1:
The return path layer is divided into multiple sections along the height direction, with each section having a different gap distance from the main magnetic pole layer. This segmentation allows different regions to serve different functions: the lower section (smaller gap) concentrates magnetic flux to increase field intensity, while the upper section (larger gap) extends the magnetic field distribution to improve gradient, thus resolving the contradiction between intensity and gradient.
Solution Approach 2:
Different gap distances are assigned to different local regions of the return path layer. The lower region has a smaller gap to enhance magnetic flux concentration and field intensity, while the upper region has a larger gap to extend field distribution and improve gradient. This local differentiation allows simultaneous optimization of both intensity and gradient that cannot be achieved with a uniform gap structure.
2Manufacturing precision
If the throat height is large, then the gradient of the magnetic field is improved, but the intensity of the recording magnetic field decreases
Solution Approach 1:
The return path layer is divided into multiple sections along the height direction, with each section having a different gap distance from the main magnetic pole layer. This segmentation allows different regions to serve different functions: the lower section (smaller gap) concentrates magnetic flux to increase field intensity, while the upper section (larger gap) extends the magnetic field distribution to improve gradient, thus resolving the contradiction between intensity and gradient.
Solution Approach 2:
Different gap distances are assigned to different local regions of the return path layer. The lower region has a smaller gap to enhance magnetic flux concentration and field intensity, while the upper region has a larger gap to extend field distribution and improve gradient. This local differentiation allows simultaneous optimization of both intensity and gradient that cannot be achieved with a uniform gap structure.
3Reliability
If the gap between main magnetic pole layer and return path layer is small, then magnetic flux dispersion is suppressed, but the area for magnetic flux flow decreases
Solution Approach 1:
The return path layer is divided into multiple sections along the height direction, with each section having a different gap distance from the main magnetic pole layer. This segmentation allows different regions to serve different functions: the lower section (smaller gap) concentrates magnetic flux to increase field intensity, while the upper section (larger gap) extends the magnetic field distribution to improve gradient, thus resolving the contradiction between intensity and gradient.
Solution Approach 2:
Instead of uniformly increasing the gap area in the horizontal direction, the invention extends the gap distance variation in the vertical (height) direction by dividing the return path layer into multiple sections. This dimensional approach allows the system to achieve both flux concentration and sufficient flux flow area by utilizing the height dimension for gap variation.
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 configuration effectively suppresses magnetic flux dispersion and maintains high magnetic field intensity, enabling improved recording performance by optimizing the gap and throat height relationships between the main magnetic pole and return path layers.
Implementation Method 1
When current is supplied to the coil layers, a recording magnetic field is induced between the main magnetic pole layer and the return path layer
Implementation Method 2
the recording magnetic field is perpendicularly applied to a hard film of the recording medium from the front end surface of the main magnetic pole layer exposed to the medium facing surface, and the recording magnetic field returns to the return path layer through a soft layer of the recording medium
Data Source
AI summary
A magnetic recording head and a method of manufacturing the magnetic recording head are provided. The perpendicular magnetic recording head includes a main magnetic pole layer and a return path layer that face each other with a gap therebetween in a lamination direction. A non-magnetic insulating layer is interposed between the main magnetic pole layer and the return path layer. At least one stepped portion is formed on a facing surface of at least one of the main magnetic pole layer and the return path layer.