Perpendicular Magnetic Recording Write Head with Separated Shields
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Solution Overview
Problem
Existing perpendicular magnetic recording write heads with wraparound shields are limited in independently controlling the magnetic properties of trailing, side, and leading shields, as they are formed from the same material and composition, restricting optimization of write head performance.
Innovation Solution
The write head design includes magnetically separated trailing, side, and leading shields, each with different materials or compositions, and adjustable throat heights, enabled by nonmagnetic separation layers, allowing independent control of magnetic permeability and flux density to tailor the magnetic field for improved write performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If trailing, side, and leading shields are formed as a single-piece wraparound shield structure, then manufacturing is simplified and structural integrity is improved, but the magnetic properties of each shield cannot be independently controlled
Solution Approach 1:
The single-piece wraparound shield is divided into separate trailing, side, and leading shield components. Each shield can be manufactured independently and then assembled together, allowing different materials and magnetic properties for each shield while maintaining manufacturing feasibility through modular construction
Solution Approach 2:
Nonmagnetic gap layers are introduced as intermediary elements between the trailing, side, and leading shields. These gap layers physically separate the shields magnetically while allowing them to be positioned in precise geometric relationships, enabling independent magnetic property control without compromising structural integrity
2Ease of manufacture
If all shields are formed of the same material and composition, then manufacturing consistency is improved, but optimization of write head performance is restricted
Solution Approach 1:
Different shields are made from different magnetic materials or different compositions of the same alloy family. The trailing shield, side shields, and leading shield can each be optimized with specific material properties tailored to their local functional requirements, such as different permeabilities or coercivities, while maintaining overall manufacturing consistency through standardized fabrication processes
3Device complexity
If shields have fixed throat heights, then manufacturing simplicity is maintained, but independent control of magnetic flux density through each shield is limited
Solution Approach 1:
The throat heights of the trailing, side, and leading shields are made adjustable rather than fixed. This can be achieved through movable shield components or adjustable positioning mechanisms that allow the throat height of each shield to be independently tuned during operation or assembly, enabling precise control of magnetic flux density through each shield while maintaining relatively simple manufacturing
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 enhances the write field gradient, reduces fringing fields, and optimizes write width and erasure control, leading to improved writing efficiency and performance in perpendicular magnetic recording.
Implementation Method 1
a trailing shield (TS) of magnetically permeable material that faces the recording layer and is spaced from the write pole in the along-the-track direction by a nonmagnetic gap
Implementation Method 2
The TS slightly alters the angle of the write field and makes writing more efficient. The side shields control the write width and eliminate adjacent-track-erasure.
Data Source
AI summary
A perpendicular magnetic recording write head that may be used in magnetic recording disk drives has a magnetic write pole (WP) with an end that is generally the same width as the width of the data tracks on the disk. A trailing shield (TS) is spaced from the WP in the along-the-track direction, a pair of side shields are located on opposite sides of the WP in the cross-track direction, and an optional leading shield (LS) is located on the opposite side of the WP from the TS in the along-the-track direction. The TS, side shields and LS are formed of magnetically permeable soft ferromagnetic material and are separated from each other by nonmagnetic separation layers. The TS, side shields and LS each has a throat height (TH) thickness in its region facing the WP. The throat heights for the shields may be different.