Arched Shield Layer in Perpendicular Magnetic Recording Head
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Solution Overview
Problem
Perpendicular magnetic recording heads face challenges in minimizing Edge Write magnetic fields and improving external magnetic field resistance due to the magnetization of return yoke and shield layers, which can lead to data overwriting and reduced field resistance.
Innovation Solution
Incorporating a second magnetic layer with a substantially arched portion in its cross-section along the height direction, and at least one of the shield layers having a similar arched shape, to reduce magnetization and minimize Edge Write magnetic fields, even when the return yoke layer is thinner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a thin magnetic body film with rectangular shape is used for return yoke layer and shield layers, then device complexity is reduced and ease of manufacture is improved, but Edge Write magnetic field increases and external magnetic field resistance deteriorates
Solution Approach 1:
The patent applies curvature to the magnetic body film by forming an arched portion in the return yoke layer and/or shield layers. This curved configuration changes the magnetization distribution, reducing the concentration of magnetic flux at edges and thereby suppressing Edge Write magnetic fields while maintaining external magnetic field resistance
2Device complexity
If a thin magnetic body film with rectangular shape is used for return yoke layer and shield layers, then device complexity is reduced, but Edge Write magnetic field increases
Solution Approach 1:
The patent introduces an arched portion in the magnetic body film structure, transforming the rectangular shape into a curved configuration. This curvature modifies the magnetic field distribution, preventing excessive concentration at edges and reducing Edge Write magnetic fields without significantly increasing device complexity
3Object-affected harmful factors
If the return yoke layer is made thinner to reduce magnetization, then external magnetic field resistance is improved, but Edge Write magnetic field increases
Solution Approach 1:
The patent applies curvature to the thin return yoke layer by forming an arched portion. This curved shape redistributes the magnetization, allowing the layer to remain thin for reduced external magnetic field interference while preventing edge concentration of magnetic flux that would cause Edge Write
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 keeps Edge Write magnetic fields low and enhances external magnetic field resistance, while also suppressing the PTP phenomenon by reducing the magnetic field component in the height direction.
Implementation Method 1
a coil layer for applying a recording magnetic field to the first magnetic layer
Implementation Method 2
In the substantially arched portion, since an external magnetic field is applied in a direction along an axis not easily magnetized, the magnetic body is not easily magnetized and the generated magnetic field becomes smaller
Data Source
AI summary
A perpendicular magnetic recording head according to the present invention is composed of a first magnetic layer having a main magnetic pole exposed at a facing surface opposite a recording medium, a second magnetic layer adjacent to the first magnetic layer with an intermediary non-magnetic layer disposed therebetween, and a coil layer for applying a recording magnetic field to the first magnetic layer. Since the second magnetic layer has a shape including a substantially arched portion in its cross section along a height direction, it becomes possible to keep an Edge Write magnetic field in a low level and improve external magnetic field resistance.