Perpendicular Magnetic Recording Element Shield Design
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Solution Overview
Problem
Perpendicular magnetic recording heads face challenges in reducing the effect of external magnetic fields, leading to adjacent track erase (ATE) and pole erase phenomena, despite existing shield structures.
Innovation Solution
A perpendicular magnetic recording element with a recording magnetic pole film and a write shield film, where the write shield film has a height equal to or smaller than the recording magnetic pole film, effectively collects leaked magnetic flux and reduces external magnetic field interference, thereby preventing ATE and pole erase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional write shield film structure is used, then the shield film can provide basic magnetic shielding, but external magnetic fields from the magnetic recording medium still penetrate and cause adjacent track erase and pole erase
Solution Approach 1:
The write shield film is extended in the thickness direction (vertical dimension) to have a height equal to or greater than the recording magnetic pole film. This dimensional extension allows the shield film to block magnetic flux from the medium surface more effectively, preventing external magnetic fields from reaching the recording layer and causing ATE or pole erase
Solution Approach 2:
The write shield film acts as an intermediary magnetic shielding layer between the external magnetic field (from the medium) and the recording magnetic pole film. By positioning the shield film to extend to the medium-facing surface, it intercepts and redirects magnetic flux before it can penetrate to the recording layer, thus protecting against ATE and pole erase
2Object-affected harmful factors
If the write shield film height is increased to block external magnetic fields, then shielding effectiveness improves, but the magnetic flux collection from the main magnetic pole may be compromised
Solution Approach 1:
The write shield film is designed with non-uniform magnetic properties in different regions: the portion facing the medium has high magnetic permeability to collect leaked flux, while the portion extending vertically provides shielding. This local differentiation allows the film to simultaneously protect against external fields and maintain efficient flux collection from the main magnetic pole
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 solution enhances recording capability by steepening the magnetic field gradient and stabilizing the write shield film's magnetization, ensuring that magnetic data remains intact and reducing the impact of external magnetic fields on the recording field.
Implementation Method 1
the write shield film, which faces the recording magnetic pole film, can widely collect a magnetic flux having leaked from the main magnetic pole
Implementation Method 2
a sufficient recording magnetic field to perform perpendicular recording can be generated at the end of the main magnetic pole by concentrating the recording magnetic field from the yoke portion to the main magnetic pole
Data Source
AI summary
A perpendicular magnetic recording element includes a recording magnetic pole film and a write shield film. The recording magnetic pole film has a yoke portion and a main magnetic pole for perpendicular recording. The main magnetic pole projects from a front end of the yoke portion to have an end on a medium-facing surface. The write shield film faces the recording magnetic pole film and has a height equal to or smaller than that of the recording magnetic pole film, as measured rearward from the medium-facing surface.