Magnetic Recording Head Oscillation Element for Stable MAMR

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Solution Overview

Problem

Magnetic disk drives face challenges in achieving high recording density, particularly in stabilizing microwave-assisted magnetic recording (MAMR) to ensure reliable data writing.

Innovation Solution

The magnetic recording head incorporates a main magnetic pole, a write shield, and an oscillation element with a non-magnetic conductive layer, featuring first and second oscillation portions with ferromagnetic and non-magnetic layers, connected by current paths to generate stable microwaves for assisting magnetization inversion in the recording medium.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If microwave-assisted magnetic recording (MAMR) is used to achieve high recording density, then recording density is improved, but stability of microwave oscillation deteriorates

Engineering Contradiction:

Improverecording densityVSAvoidmicrowave oscillation stability

Core Design Contradiction:

Quantity of substanceVSStability of the object's composition

Solution Approach 1:

A non-magnetic conductive layer is introduced as an intermediary between the first and second ferromagnetic layers. This conductive layer serves as a stable reference potential that mediates the interaction between the two ferromagnetic layers, enabling consistent spin current flow and stable microwave oscillation. The non-magnetic conductive layer acts as a buffer that decouples the magnetic interactions while maintaining electrical connectivity, thus stabilizing the microwave generation process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The oscillation element employs a composite multilayer structure consisting of ferromagnetic layers, non-magnetic layers, and a non-magnetic conductive layer. This composite structure combines materials with different magnetic and electrical properties to achieve both high recording density through spin transfer torque and stable microwave oscillation. The specific combination of CoFeB, Ru, and Cu layers creates a system where spin polarized current can be efficiently generated while maintaining oscillation stability.

Inventive Principle:

Principle #40Composite materials

2Device complexity

If a simple oscillation element structure is used, then device complexity is reduced, but microwave oscillation stability deteriorates

Engineering Contradiction:

Improveoscillation element structureVSAvoidmicrowave oscillation stability

Core Design Contradiction:

Device complexityVSStability of the object's composition

Solution Approach 1:

The oscillation element is segmented into distinct functional layers: first ferromagnetic layer, non-magnetic layer, non-magnetic conductive layer, second ferromagnetic layer, and second non-magnetic layer. Each layer has a specific function - the first and second ferromagnetic layers generate spin polarized current, the non-magnetic conductive layer provides stable electrical reference, and the non-magnetic layers provide structural support and magnetic decoupling. This segmentation allows for optimized performance of each component while maintaining overall stability.

Inventive Principle:

Principle #1Segmentation

3Power

If high current density is applied to generate microwaves, then microwave power is increased, but energy loss increases

Engineering Contradiction:

Improvemicrowave powerVSAvoidenergy loss

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent optimizes the thickness and material composition parameters of each layer to achieve efficient spin transfer torque at reduced current densities. The CoFeB ferromagnetic layers with specific thickness (5-20 nm) and the Ru non-magnetic spacer layers are designed to maximize spin polarization while minimizing resistive heating. The non-magnetic conductive layer with high electrical conductivity (such as Cu with thickness 10-50 nm) reduces ohmic losses, enabling efficient microwave generation at lower power consumption.

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 configuration enables stable oscillation of microwaves, enhancing the writing efficiency and reliability of data storage by ensuring consistent magnetization inversion in the magnetic recording medium, thus improving the overall stability and reliability of the magnetic disk drive.

Implementation Method 1

The oscillation element has a first current path connecting the main magnetic pole and the non-magnetic conductive layer to each other, and a second current path connecting the write shield and the non-magnetic conductive layer to each other. This magnetic recording head can stably oscillate microwaves.

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 2

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 3

The main magnetic pole leads to an air bearing surface and generates a recording magnetic field.

Methodology Applied

Scientific EffectElectromagnetic field generation: Electromagnet

Data Source

PatentUS20230131758A1Magnetic recording head having a magnetic pole and a write shield

Publication Date: 2023.04.27 TDK CORP

AI summary

This magnetic recording head includes a main magnetic pole, a write shield, and an oscillation element. The oscillation element has a first oscillation portion, a second oscillation portion, and a non-magnetic conductive layer provided therebetween. The oscillation element has a first current path connecting the main magnetic pole and the non-magnetic conductive layer to each other, and a second current path connecting the write shield and the non-magnetic conductive layer to each other.