Dual Oscillation Layer STO for Stable RF Field Generation

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Solution Overview

Problem

In radio frequency magnetic field assisted recording, energy loss occurs due to unstable magnetization of the magnetic pole when the distance between the spin torque oscillator (STO) and the magnetic pole is short, leading to a reduction in the generation rate of the radio frequency magnetic field.

Innovation Solution

The use of a dual oscillation layer structure in the STO, where the second oscillation layer is closer to the magnetic pole than the first oscillation layer, allows for a more effective generation of the radio frequency magnetic field while minimizing energy loss by ensuring the magnetization of the magnetic pole remains stable, achieved through appropriate material selection and layering to adjust saturated magnetization and anisotropy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the distance between the STO and the magnetic pole is short, then the radio frequency magnetic field and recording magnetic field can be efficiently superposed on the magnetic recording medium, but the radio frequency magnetic field generated from the oscillation layer is applied to the magnetic pole causing energy loss and reducing the generation rate of the radio frequency magnetic field

Engineering Contradiction:

Improvegeneration rate of radio frequency magnetic fieldVSAvoidenergy loss due to unstable magnetization of magnetic pole

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The oscillation layer is divided into a first oscillation layer and a second oscillation layer with different functions. The first oscillation layer is positioned to generate radio frequency magnetic field for recording, while the second oscillation layer is positioned to minimize energy loss by being farther from the magnetic pole. This segmentation allows each layer to optimize its position for its specific function.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the STO are given different properties: the first oscillation layer has properties optimized for generating strong radio frequency magnetic field at the recording interface, while the second oscillation layer has properties optimized for minimizing energy loss by being positioned farther from the magnetic pole. This local differentiation resolves the contradiction between efficiency and energy loss.

Inventive Principle:

Principle #3Local quality

2Productivity

If the distance between the STO and the magnetic pole is short, then efficient superposition of magnetic fields is achieved, but magnetization of the magnetic pole becomes unstable

Engineering Contradiction:

Improverecording efficiencyVSAvoidstability of magnetization of magnetic pole

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The oscillation layer is segmented into two distinct layers with different positions relative to the magnetic pole. The first oscillation layer maintains short distance for efficient recording, while the second oscillation layer is positioned to avoid applying strong radio frequency magnetic field to the magnetic pole, thus maintaining magnetization stability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The second oscillation layer acts as an intermediary element that mediates between the radio frequency magnetic field generation and the magnetic pole. It provides a buffer zone that prevents direct strong interaction between the oscillation layer and magnetic pole, maintaining stability while allowing recording function.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 the generation of a stable radio frequency magnetic field with reduced energy loss and increased recording density, independent of the recording polarity, resulting in a lower bit error rate.

Implementation Method 1

A spin torque oscillator (STO) including an oscillation layer and a spin injection layer can generate a radio frequency magnetic field by applying current to the STO. This is because magnetization of the oscillation layer can oscillate itself.

Methodology Applied

Scientific EffectSpin torque oscillation:

Implementation Method 2

A magnetic pole can then generate a recording magnetic field.

Methodology Applied

Scientific EffectMagnetic field generation: Magnetic Field

Implementation Method 3

A radio frequency magnetic field and a recording magnetic field can be efficiently superposed on the magnetic recording medium if the distance between the STO and the magnetic pole is short.

Methodology Applied

Scientific EffectMagnetic field superposition: Magnetic Field

Data Source

PatentUS8559134B2Radio frequency magnetic field assisted recording head, head assembly, amd recording apparatus

Publication Date: 2013.10.15 KK TOSHIBA

AI summary

A recording head including a first electrode, a first magnetic layer, a second magnetic layer, a first intermediate layer, a third magnetic layer, a second electrode, and a magnetic pole. A product of saturated magnetization of the first magnetic layer and a lateral area of the first magnetic layer is larger than a product of saturated magnetization of the third magnetic layer and a lateral area of the third magnetic layer.