Magnetic Recording Head With Dual High-Frequency Oscillators

Solution Overview

Problem

Conventional magnetic recording heads for high-frequency assist recording struggle to increase recording density in the cross-track direction due to a small gradient of the high-frequency magnetic field, limiting the surface recording density.

Innovation Solution

Incorporating a pair of high-frequency oscillators, such as spin-torque oscillators, between the main pole and side shields in the magnetic recording head, which increases the gradient of the high-frequency magnetic field in the cross-track direction, thereby enhancing the surface recording density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the width of the main pole is increased to increase the intensity of the recording magnetic field, then the recording magnetic field intensity is improved, but the gradient of the high-frequency magnetic field in the cross-track direction deteriorates

Engineering Contradiction:

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The patent divides the single high-frequency oscillator into a pair of oscillators positioned on opposite sides of the main pole in the cross-track direction. This segmentation allows each oscillator to contribute to the overall magnetic field while creating a steeper gradient through their combined effect, resolving the contradiction between field intensity and gradient.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent places high-frequency oscillators at specific locations (between the main pole and side shields) to create localized high-frequency magnetic fields with steep gradients. This local quality approach ensures that the gradient enhancement occurs precisely where needed in the cross-track direction without compromising overall field intensity.

Inventive Principle:

Principle #3Local quality

2Force

If a single high-frequency oscillator is placed between the main pole and write shield, then the high-frequency magnetic field intensity is improved, but the gradient of the high-frequency magnetic field in the cross-track direction deteriorates

Engineering Contradiction:

Core Design Contradiction:

ForceVSManufacturing precision

Solution Approach 1:

The patent segments the single oscillator configuration into a pair of oscillators positioned symmetrically on opposite sides of the main pole. This segmentation transforms the field distribution to achieve both high intensity and steep gradient in the cross-track direction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent utilizes symmetric placement of oscillators relative to the main pole centerline, creating an asymmetric field distribution pattern that produces steep gradients in the cross-track direction while maintaining high overall field intensity through constructive interference.

Inventive Principle:

Principle #4Asymmetry

3Reliability

If the width of the main pole is increased to enable recording on medium with greater coercive force, then the recording capability on high-coercive-force medium is improved, but the recording density in the cross-track direction deteriorates

Engineering Contradiction:

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The patent employs a pair of side shields and corresponding oscillators to segment the magnetic field distribution in the cross-track direction. This segmentation creates sharper field transitions that increase cross-track recording density while the main pole width remains sufficient for recording on high-coercive-force media.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the spatial distribution parameters of the high-frequency magnetic field by introducing oscillators at specific positions between the main pole and side shields. This parameter change creates steep gradients that increase cross-track density without requiring changes to the main pole width, thus preserving recording capability on high-coercive-force media.

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

The increased gradient of the high-frequency magnetic field leads to improved recording density in the cross-track direction, resulting in a magnetic recording head with increased surface recording capacity.

Implementation Method 1

Incorporating a pair of high-frequency oscillators, such as spin-torque oscillators, between the main pole and side shields in the magnetic recording head

Methodology Applied

Scientific EffectSpin-torque oscillator effect:

Implementation Method 2

a main pole configured to apply a recording magnetic field to a recording layer included in a recording medium

Methodology Applied

Scientific EffectMagnetic field generation: Magnetic Field

Data Source

PatentUS9076463B2Magnetic recording head and disk device with the same

Publication Date: 2015.07.07

AI summary

According to one embodiment, a magnetic head includes a main pole configured to apply a recording magnetic field to a recording layer included in a recording medium, a trailing shield opposing the main pole in a down-track direction, with a write gap interposed therebetween, a pair of side shields opposing the main pole on opposite sides of the main pole in a cross-track direction, with respective gaps interposed therebetween, a recording coil configured to cause the main pole to generate a magnetic field, a first high-frequency oscillator interposed between the main pole and one of the side shields, and a second high-frequency oscillator interposed between the main pole and the other side shield.