Recessed Electron Spin Analyzer for Magnetic Recording Heads

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Solution Overview

Problem

Current magnetic recording heads face challenges in reducing shield-to-shield spacing due to the thickness of layers required, which affects signal pulse width as track density increases, particularly at bit sizes below 20 nm.

Innovation Solution

The design incorporates a recessed electron spin analyzer with a nonmagnetic conductor layer between the polarizer and sensor layers, allowing the polarizer's magnetization to extend beyond the air bearing surface, reducing the effective shield-to-shield spacing while preserving electron spin signals for analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If traditional magnetic recording head design is used with all layers positioned at the air bearing surface, then the sensor stack can be fully integrated, but the shield-to-shield spacing becomes too large which worsens signal pulse width at high track densities

Engineering Contradiction:

Improveshield-to-shield spacingVSAvoidsignal pulse width

Core Design Contradiction:

Length of moving objectVSManufacturing precision

Solution Approach 1:

The patent positions the analyzer layer recessed from the air bearing surface in a different spatial dimension (z-direction), while the polarizer remains at the air bearing surface. This dimensional separation allows the shield-to-shield spacing to be reduced without compromising the sensor stack's functional integrity, as the analyzer can still detect spin signals through the nonmagnetic conductor layer from its recessed position.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The analyzer layer is nested within the space between the shields at a recessed position, rather than requiring full integration at the air bearing surface. This nesting approach allows multiple functional layers to be arranged in a compact configuration that reduces overall shield-to-shield spacing while maintaining all necessary sensing functions.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Length of moving object

If the sensor stack is recessed from the air bearing surface, then shield-to-shield spacing is reduced, but the complexity of layer positioning and alignment increases

Engineering Contradiction:

Improveshield-to-shield spacingVSAvoidlayer positioning complexity

Core Design Contradiction:

Length of moving objectVSDevice complexity

Solution Approach 1:

The sensor stack is segmented into two distinct groups: layers at the air bearing surface (cap, polarizer) and layers recessed from it (analyzer, bottom shield). This segmentation allows each group to be optimized independently for its specific function, simplifying the overall design despite the recessed configuration.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A nonmagnetic conductor layer serves as an intermediary between the polarizer at the air bearing surface and the analyzer recessed from it. This intermediary layer facilitates spin signal transmission across the spatial gap, enabling the recessed analyzer to function effectively without requiring direct contact with the air bearing surface layers.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If layer thickness is increased to accommodate all sensor layers at the air bearing surface, then manufacturing is simplified, but signal pulse width deteriorates due to larger shield-to-shield spacing

Engineering Contradiction:

Improvelayer integrationVSAvoidsignal pulse width

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

By moving the analyzer layer to a recessed position in the z-direction (perpendicular to the air bearing surface), the patent eliminates the need to increase in-plane layer thickness to accommodate all sensor layers. This dimensional repositioning maintains compact shield-to-shield spacing while preserving manufacturing feasibility through standardized layer deposition processes.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration enables a reduced shield-to-shield spacing, improving signal pulse width and efficiency in data reading from high-density magnetic media by maintaining spin signal integrity and allowing for more compact sensor designs.

Implementation Method 1

The nonmagnetic conductor layer is positioned between the polarizer and the first sensor layer

Methodology Applied

Scientific EffectElectron spin transport:

Implementation Method 2

allowing the polarizer's magnetization to extend beyond the air bearing surface, reducing the effective shield-to-shield spacing

Methodology Applied

Scientific EffectMagnetization extension: Magnetism

Implementation Method 3

a sensor stack having a first sensor layer... A magnetization of the first sensor layer is arranged and configured to move in the same direction as a magnetization of the polarizer

Methodology Applied

Scientific EffectMagnetic detection: Magnetic Field

Data Source

PatentUS8929034B2Devices and methods using recessed electron spin analyzers

Publication Date: 2015.01.06 SEAGATE TECH LLC

AI summary

In certain embodiments, an apparatus includes a top shield, bottom shield, polarizer, nonmagnetic conductor layer, and a sensor stack having a first sensor layer. The sensor stack is positioned at a distance recessed from a first plane. The nonmagnetic conductor layer is positioned between the polarizer and the first sensor layer. A magnetization of the first sensor layer is arranged and configured to move in the same direction as a magnetization of the polarizer.