Magnetic Recording Head Write Gap Reduction via Spin-Torque Oscillator Extraction

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Solution Overview

Problem

Existing magnetic recording heads with spin-torque oscillators are not compatible with the shingled recording method and have a widened write gap due to electrode terminals and insulating layers, which negatively impacts linear recording density.

Innovation Solution

A magnetic recording head design featuring a slider with a main magnetic pole, a write shield magnetic pole, and two spin-torque oscillators in the write gap, where an insulating layer is used between them, and a current circuit connects the spin-torque oscillators to the main and write shield magnetic poles, allowing for selective energization direction switching to optimize recording quality and reduce the write gap.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrode terminals and insulating layers are provided inside each spin-torque oscillator, then the spin-torque oscillator can be energized and function properly, but the write gap becomes wider which reduces linear recording density

Engineering Contradiction:

Improvespin-torque oscillator functionalityVSAvoidwrite gap width

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent extracts the electrode terminal and insulating layer from the spin-torque oscillator structure, eliminating components that contribute to write gap width while preserving the essential oscillation function through direct magnetization control

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the spin-torque oscillator functionality directly into the magnetic pole structure, combining the oscillation element with the pole piece to eliminate separate electrode terminals and insulating layers, thereby reducing write gap width while maintaining oscillator functionality

Inventive Principle:

Principle #5Merging (Combining)

2Reliability

If multiple spin-torque oscillators are arranged in the write gap, then recording quality can be improved, but the device complexity increases

Engineering Contradiction:

Improverecording qualityVSAvoidnumber of spin-torque oscillators and their connections

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the magnetic pole structure serve multiple functions: it acts as both the magnetic field generation element and the electrode terminal for the spin-torque oscillators, eliminating the need for separate electrode terminals and insulating layers, thereby reducing device complexity while maintaining the ability to support multiple oscillators for improved recording quality

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 recording quality and linear recording density by allowing for narrower write gaps and improved magnetic field distribution, enabling effective shingled recording and reducing the transition width of magnetization.

Implementation Method 1

a high-frequency assisted head has been proposed, which includes a high-frequency oscillator, such as a spin-torque oscillator, in the write gap between the write shield magnetic pole and the main magnetic pole

Methodology Applied

Scientific EffectSpin-torque oscillator:

Implementation Method 2

a coil, which causes a magnetic flux to flow through the main magnetic pole

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a main magnetic pole, which generates a perpendicular direction magnetic field

Methodology Applied

Scientific EffectMagnetic field generation: Magnetic Field

Data Source

PatentUS10714126B2Magnetic recording head and disk device including the same

Publication Date: 2020.07.14 KK TOSHIBA

AI summary

A magnetic recording head includes a slider having an air bearing surface, a main magnetic pole including a fore-end portion that extends towards the air bearing surface and configured to generate recording magnetic fields in a first direction, a write shield magnetic pole located across from the fore-end portion to form a write gap that extends therebetween in a second direction and forming a magnetic core in conjunction with the main magnetic pole, a coil configured to excite a magnetic flux in the magnetic core, first and second spin-torque oscillators in the write gap and arranged along a third direction with a spacing therebetween, and a current circuit connected to the first and second spin-torque oscillators via the main magnetic pole and the write shield magnetic pole and configured to supply current to oscillate the first or second spin-torque oscillators.