PMR Write Head with Tunable Two-Branch Bias Paths
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Solution Overview
Problem
Existing perpendicular magnetic recording (PMR) write heads face challenges in achieving high storage density and efficient current distribution due to limitations in bias branch configurations, which affect the writeability and coherence of the main pole and hot seed tip.
Innovation Solution
A PMR write head with a tunable two bias branch design that electrically separates the trailing shield, side shield, and leading shield using insulation layers and multiple electrical paths, allowing independent adjustment of current flow through the write gap and side/leading gaps, enhancing the coherence and writeability of the main pole.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single bias branch configuration is used in existing PMR write heads, then the structure is simple, but the writeability and coherence of the main pole and hot seed tip are insufficient
Solution Approach 1:
The single bias branch is segmented into two separate bias branches: a first bias branch connecting the trailing shield to the main pole through the write gap, and a second bias branch connecting the side shield and leading shield to the main pole through the side gap and leading gap. This segmentation allows independent current path control for each shield component, improving writeability and coherence without excessive complexity
Solution Approach 2:
The bias branch configuration is made dynamically adjustable by introducing tunable elements (such as variable resistors or switches) in each bias branch, allowing the current distribution ratios to be optimized based on recording conditions, thereby enhancing writeability while maintaining manageable complexity
2Reliability
If current flow through write gap and side/leading gaps is not independently controlled, then the structure is simple, but storage density and coherence are limited
Solution Approach 1:
The electrical paths are segmented into distinct first and second bias branches, with the first branch controlling current through the write gap and the second branch controlling current through the side gap and leading gap. This segmentation enables independent control of current flow in different regions, improving coherence and storage density
Solution Approach 2:
Each bias branch is designed with local characteristics optimized for its specific function: the first bias branch is optimized for write gap current control affecting the main pole tip, while the second bias branch is optimized for side and leading gap current control affecting the side shields. This local optimization enhances overall system performance
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 improves writeability and high-frequency response by allowing independent tuning of current ratios through separate bias branches, thereby increasing storage density and reliability without altering existing pad layouts or requiring additional resources.
Implementation Method 1
an insulation layer disposed between the trailing shield and the side shield
Implementation Method 2
a width of the conducting WG corresponds with a width of the main pole
Implementation Method 3
a main pole including a tip portion configured to be disposed at an air-bearing surface (ABS) and configured to interact with a magnetic recording medium
Data Source
AI summary
The present embodiments relate to a perpendicular magnetic recording (PMR) write head with a Two Tunable bias branch design that can electrical separate a WS1/PP3 and a SS/LS to form two tunable bias branches. A write head can include a main pole, a write gap(WG) disposed adjacent to the main pole, and a hot seed (HS) layer connected to the WG. The PMR write head can also include a trailing shield, a side shield and a leading shield. Two tunable bias branches can be formed to electrically separate the trailing shield and the side and leading shields. A first branch can include a first electrical path between the main pole and the trailing shield. The tunable bias branches can also include a second branch forming a second electrical path between the main pole and the side and leading shields.