Magnetic Writer Shield Saturation Magnetization Gradient

Solution Overview

Problem

Conventional magnetic recording heads face issues with wide area track erasure due to mismatches in saturation magnetizations between shields and return poles, leading to flux leakage and performance degradation at higher areal densities.

Innovation Solution

Implementing a gradient in saturation magnetization in the leading, trailing shields, and return poles to reduce mismatches at interfaces, achieved through varying the composition or layering of materials, ensuring that saturation magnetization increases or decreases in a controlled manner towards the main pole and side shields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional magnetic recording heads are used, then basic recording function is maintained, but wide area track erasure occurs due to saturation magnetization mismatch between shields and return poles

Engineering Contradiction:

Improverecording reliabilityVSAvoidwide area track erasure

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies local quality by creating a gradient in saturation magnetization specifically at the interfaces between shields and return poles. The saturation magnetization is varied locally in the down-track direction, with different regions having different magnetization values to optimize flux containment at critical interfaces while maintaining overall head structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the magnetic parameter (saturation magnetization) of the shield and return pole materials. By adjusting the saturation magnetization values and creating gradients in the down-track direction, the patent optimizes the magnetic properties to reduce flux leakage and eliminate wide area track erasure while maintaining recording reliability.

Inventive Principle:

Principle #35Parameter changes

2Quantity of substance

If higher areal densities are pursued, then recording capacity increases, but track width decreases leading to performance degradation

Engineering Contradiction:

Improveareal densityVSAvoidtrack width control

Core Design Contradiction:

Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent applies local quality by creating a gradient in saturation magnetization specifically at the interfaces between shields and return poles. The saturation magnetization is varied locally in the down-track direction, with different regions having different magnetization values to optimize flux containment at critical interfaces while maintaining overall head structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the magnetic parameter (saturation magnetization) of the shield and return pole materials. By adjusting the saturation magnetization values and creating gradients in the down-track direction, the patent optimizes the magnetic properties to reduce flux leakage and eliminate wide area track erasure while maintaining recording reliability.

Inventive Principle:

Principle #35Parameter changes

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 approach improves the performance of magnetic recording heads by reducing sharp transitions in magnetic properties, addressing wide area track erasure and other issues, while maintaining the desired low, high, and intermediate saturation magnetization levels.

Implementation Method 1

at least one of the leading shield, the trailing shield, and the return pole has a gradient in saturation magnetization such that the mismatch in saturation magnetization at various interfaces is reduced or eliminated

Methodology Applied

Scientific EffectSaturation magnetization gradient: Magnetic Saturation

Data Source

PatentUS9443541B1Magnetic writer having a gradient in saturation magnetization of the shields and return pole

Publication Date: 2016.09.13 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A method and system provide a magnetic transducer. The transducer includes a main pole, a side gap, at least one coil, a side shield and at least one of a leading shield, a trailing shield and a return pole. The coil(s) are configured to energize the main pole. The side gap is between the main pole and the side shield. The main pole is between the leading shield and the trailing shield. The trailing shield is between the main pole and the return pole. The side shield is between the leading shield and the trailing shield. At least one of the leading shield, the trailing shield and the return pole have a gradient in saturation magnetization such that the saturation magnetization varies in a down track direction.