PMR Write Head Two-Branch Biasing for High-Frequency Response

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Solution Overview

Problem

Existing perpendicular magnetic recording (PMR) write heads face challenges in optimizing storage density and writer performance due to limitations in current bias branch designs, which affect the efficiency and reliability of data storage in hard disk drives.

Innovation Solution

A perpendicular magnetic recording (PMR) write head with a tunable two bias branch design that electrically separates the trailing shield from the side shield and leading shield, incorporating insulation layers and multiple electrical paths to adjust current flow ratios, enhancing writer performance and storage density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single bias branch design is used in PMR write heads, then the device complexity is low, but the writer high-frequency response and storage density optimization are limited

Engineering Contradiction:

Improvewriter high-frequency responseVSAvoidbias branch design

Core Design Contradiction:

ReliabilityVSDevice complexity

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, and a second bias branch connecting the side shield and leading shield to the main pole. This segmentation allows independent optimization of current paths, improving writer high-frequency response while maintaining manageable device complexity through modular design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bias branch design is made tunable and adjustable, allowing dynamic optimization of current flow ratios. The insulating layer thickness and material properties can be adjusted to control the distribution of current between the two branches, enabling adaptation to different operating conditions and frequency requirements.

Inventive Principle:

Principle #15Dynamics

2Productivity

If insulation layers are added to electrically separate shields and form two bias branches, then storage density and writer performance improve, but the manufacturing complexity increases

Engineering Contradiction:

Improvestorage densityVSAvoidinsulation layer integration

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

An insulating layer is introduced as an intermediary element between the trailing shield and the side shield/leading shield. This insulating layer electrically separates the two shields, enabling the formation of two distinct bias branches. The insulating layer can be integrated into existing manufacturing processes as an additional deposition step, allowing performance improvement without fundamentally changing the manufacturing approach.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If the trailing shield is electrically separated from the side shield and leading shield, then independent current flow adjustment is enabled, but the device structure becomes more complex

Engineering Contradiction:

Improvecurrent flow adjustmentVSAvoidelectrical separation structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The electrical separation structure is designed to be tunable, with the insulating layer's properties (thickness, material composition) adjustable to control current flow distribution. This dynamic capability allows the device to adapt to different operating conditions and optimize current flow ratios between the two bias branches, enhancing versatility while keeping the structural complexity manageable through controlled variability.

Inventive Principle:

Principle #15Dynamics

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 tunable bias branches improve writer high-frequency response, increase storage density, and enhance reliability by allowing independent adjustment of current flow through separate branches, optimizing the write head's performance without altering existing pad layouts or requiring additional resources.

Implementation Method 1

An insulation layer can be disposed between the trailing shield and the side shield and leading shield, thereby forming the two bias branches

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

a perpendicular magnetic recording (PMR) write head... configured to interact with a magnetic recording medium... modify a magnetization of the disk

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20250329343A1Perpendicular Magnetic Recording Writer with Tunable Two Bias Branches

Publication Date: 2025.10.23 HEADWAY TECHNOLOGIES INC

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.