HAMR Recording Head Recessed Trailing Return Pole

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Solution Overview

Problem

Heat-assisted magnetic recording (HAMR) technology faces challenges in maintaining optimal head-to-media spacing and achieving high areal density capacity due to thermal expansion of recording head components, which can lead to interference with the recording medium and reduced performance.

Innovation Solution

A recording head design featuring a recessed portion relative to the media-facing surface, with the trailing return pole positioned within this recessed area, allows for closer proximity of the near-field transducer and write pole to the recording medium, reducing thermal expansion interference and enabling improved performance through precise control of head-to-media spacing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the recording head components are positioned closer to the recording medium to achieve high areal density capacity, then the areal density capacity is improved, but thermal expansion of the components causes interference with the recording medium

Engineering Contradiction:

Improveareal density capacityVSAvoidthermal expansion interference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The recessed portion is formed in advance during manufacturing to pre-compensate for thermal expansion that will occur during operation. This preliminary structural adjustment ensures that even when thermal expansion occurs, the trailing return pole remains properly positioned and does not interfere with the recording medium, allowing the head to maintain optimal spacing at higher areal densities

Inventive Principle:

Principle #9Preliminary anti-action

2Use of energy by moving object

If the near-field transducer and write pole are positioned closer to the recording medium, then the laser current requirement is reduced, but the head-to-media spacing control becomes more challenging due to thermal expansion

Engineering Contradiction:

Improvelaser current requirementVSAvoidhead-to-media spacing control

Core Design Contradiction:

Use of energy by moving objectVSEase of operation

Solution Approach 1:

The recessed portion creates a localized structural feature that specifically addresses the spacing control issue for the trailing return pole without affecting the positioning of the near-field transducer and write pole. This local structural modification allows the critical components to be positioned closer to the media for reduced laser current while the recessed area accommodates thermal expansion of the trailing return pole separately

Inventive Principle:

Principle #3Local quality

3Reliability

If the trailing return pole is positioned closer to the recording medium to improve magnetic flux return, then the magnetic recording performance is improved, but thermal expansion causes the pole to interfere with the recording medium

Engineering Contradiction:

Improvemagnetic recording performanceVSAvoidthermal expansion interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The recessed portion is pre-formed to anticipate and accommodate thermal expansion of the trailing return pole during operation. This preliminary structural compensation allows the pole to be positioned close to the recording medium for optimal magnetic flux return while preventing thermal expansion from causing interference with the media

Inventive Principle:

Principle #9Preliminary anti-action

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 HAMR performance by reducing required laser current, minimizing track width, increasing areal density capacity, and maintaining optimal thermal gradient, while also facilitating contact detection and clearance control.

Implementation Method 1

a near-field transducer extending to a media-facing surface of the recording head

Methodology Applied

Scientific EffectOptical energy concentration: Focusing

Implementation Method 2

maintaining optimal thermal gradient

Methodology Applied

Scientific EffectThermal gradient: Temperature Gradient

Implementation Method 3

a write pole extending to a media-facing surface of the recording head

Methodology Applied

Scientific EffectMagnetic field generation: Electromagnet

Implementation Method 4

thermal expansion of recording head components, which can lead to interference with the recording medium

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS11763847B1Heat-assisted magnetic recording head, and related methods

Publication Date: 2023.09.19 SEAGATE TECH LLC

AI summary

The present disclosure relates to a recording head that includes a write pole extending to a media-facing surface of the recording head; a near-field transducer extending to a media-facing surface of the recording head; a trailing return pole positioned between the write pole and the trailing edge; and a recessed portion that is recessed relative to the media-facing surface by a distance when no power is applied to the recording head. The trailing return pole is located in the recessed portion. The present disclosure also includes relates methods of making and detecting contact between a recording head and recording medium.