Spin Torus Oscillator Antiferromagnetic Assist Layer

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Solution Overview

Problem

Many spin torque oscillator (STO) devices that generate periodic pulses above 10 GHz suffer from broad peak widths and low Q factors at the oscillation frequency, limiting their performance in communication and other electronic applications.

Innovation Solution

A spin torque oscillator design incorporating an antiferromagnetically coupled assist layer, featuring a device layer stack with a spin polarization layer, a ferromagnetic oscillation layer, a nonmagnetic spacer layer, and an antiferromagnetically coupled assist layer, along with a bias magnetic field and electrode configurations to enhance frequency stability and Q factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional spin torque oscillator devices are used to generate periodic pulses above 10 GHz, then high frequency generation is achieved, but broad peak width and low Q factor occur

Engineering Contradiction:

Improveoscillation frequencyVSAvoidpeak width at oscillation frequency

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The oscillator is divided into multiple functional layers including a spin polarization layer, ferromagnetic oscillation layer, and assist layer with antiferromagnetic coupling. This segmentation allows each layer to perform specific functions: the spin polarization layer generates spin-polarized current, the ferromagnetic oscillation layer produces the oscillation, and the assist layer with antiferromagnetic coupling narrows the peak width, thereby achieving high frequency with narrow peak width

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The device employs composite magnetic layer structures with different magnetic properties. The combination of ferromagnetic materials with antiferromagnetic coupling creates a composite system where the assist layer's magnetization is coupled to the ferromagnetic oscillation layer, resulting in narrowed peak width while maintaining high oscillation frequency operation

Inventive Principle:

Principle #40Composite materials

2Speed

If conventional spin torque oscillator devices are used to generate periodic pulses above 10 GHz, then high frequency generation is achieved, but low Q factor occurs

Engineering Contradiction:

Improveoscillation frequencyVSAvoidQ factor at oscillation frequency

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

By segmenting the oscillator into distinct functional layers, the invention isolates the frequency-determining elements from damping sources. The spin polarization layer and ferromagnetic oscillation layer generate high frequency oscillations, while the assist layer with antiferromagnetic coupling specifically addresses peak width without introducing additional damping, thereby maintaining high Q factor

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The assist layer acts as an intermediary element that mediates between the spin polarization layer and the ferromagnetic oscillation layer. Through antiferromagnetic coupling, it provides the necessary magnetic interaction to narrow the peak width while maintaining the oscillation frequency and Q factor, effectively mediating the magnetic field interactions in the device

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

The design achieves a narrower peak width at the oscillation frequency, improving the Q factor and performance of STOs in communication devices, enabling more efficient generation of high-frequency periodic signals.

Implementation Method 1

The assist layer is antiferromagnetically coupled to the ferromagnetic oscillation layer through the non-magnetic coupling layer

Methodology Applied

Scientific EffectAntiferromagnetic coupling: Magnetism

Implementation Method 2

spin torque oscillator

Methodology Applied

Scientific EffectSpin torque:

Data Source

PatentUS11239016B2Spin torque oscillator with an antiferromagnetically coupled assist layer and methods of operating the same

Publication Date: 2022.02.01 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A spin torque oscillator includes a first electrode, a second electrode and a device layer stack located between the first electrode and the second electrode. The device layer stack includes a spin polarization layer including a first ferromagnetic material, an assist layer including a third ferromagnetic material, a ferromagnetic oscillation layer including a second ferromagnetic material located between the spin polarization layer and the assist layer, a nonmagnetic spacer layer located between the spin polarization layer and the ferromagnetic oscillation, and a nonmagnetic coupling layer located between the ferromagnetic oscillation layer and the assist layer. The assist layer is antiferromagnetically coupled to the ferromagnetic oscillation layer through the non-magnetic coupling layer, and the assist layer has a magnetization that is coupled to a magnetization of the ferromagnetic oscillation layer.