Single Magnetic Layer Microwave Oscillator Design

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Solution Overview

Problem

Current technologies face challenges in generating microwave frequency signals within the Terahertz gap (0.3 to 30 THz) efficiently, as conventional methods either require complex multi-layer magnetic structures or struggle with integration and cost-effectiveness.

Innovation Solution

A method and system for generating voltage and current oscillations in a single magnetic layer using a ferrimagnetic or antiferromagnetic material with specific sub-lattice structures, applying direct voltage or current to induce spin-orbit torque and magnetization precession, thereby producing oscillatory conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If multi-layer magnetic structures are used to generate microwave signals, then the frequency range can be extended, but the device complexity and fabrication difficulty increase

Engineering Contradiction:

Improvefrequency rangeVSAvoiddevice complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the non-magnetic spacer layer from the conventional STT oscillator structure, using only a single magnetic layer to generate microwave signals. This simplifies the device structure while maintaining the ability to generate frequencies in the desired range through current-induced magnetization precession in the single layer.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the functions of multiple layers into a single magnetic layer. The single layer performs both the magnetization precession and signal generation functions that traditionally required separate reference and free layers, reducing fabrication steps and device complexity.

Inventive Principle:

Principle #5Merging (Combining)

2Speed

If multi-layer magnetic structures are used, then microwave signal generation is achieved, but fabrication process becomes complicated

Engineering Contradiction:

Improvemicrowave signal generationVSAvoidfabrication process

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent removes the non-magnetic spacer layer and reference layer, leaving only a single magnetic layer that can be fabricated using simpler deposition processes. This eliminates the need for precise interface control between multiple layers while maintaining microwave signal generation capability.

Inventive Principle:

Principle #2Taking out (Extraction)

3Speed

If conventional VCOs are used, then microwave signals can be generated, but integration with silicon technology and cost-effectiveness are reduced

Engineering Contradiction:

Improvemicrowave signal generationVSAvoidintegration with silicon technology

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The patent replaces the mechanical and electronic components of conventional VCOs (crystals, amplifiers, varicaps) with a single-layer spintronic device that generates microwave signals through magnetization precession. This solid-state approach enables direct integration with silicon technology and reduces component count.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach simplifies the generation of microwave frequency signals by reducing the number of magnetic layers required, enabling frequencies beyond existing semiconductor and magnetic technologies, with potential for more efficient and cost-effective integration.

Implementation Method 1

applying direct voltage or current to induce spin-orbit torque and magnetization precession

Methodology Applied

Scientific EffectSpin-orbit torque:

Implementation Method 2

angular moment carried by the spin-polarised current emitted from the reference layer, upon transmission through the spacer layer, exerts sufficient torque (i.e. STT) on the magnetisation vector M2 of the free layer

Methodology Applied

Scientific EffectSpin transfer torque:

Implementation Method 3

The resulting time varying resistance of the multi-layer stack 100 via the giant magnetoresistance (GMR) effect

Methodology Applied

Scientific EffectGiant magnetoresistance: Magnetoresistance

Implementation Method 4

or tunneling magnetoresistance (TMR) effect where the non-magnetic layer 120 is a dielectric

Methodology Applied

Scientific EffectTunneling magnetoresistance: Magnetoresistance

Data Source

PatentUS11533020B2Single magnetic-layer microwave oscillator

Publication Date: 2022.12.20 THE PROVOST FELLOWS FOUNDATION SCHOLARS AND THE OTHER MEMBERS OF BOARD OF THE COLLEGE OF THE HOLLY & UNDIVIDED TRINITY OF QUEEN ELIZABETH NEAR DUBLIN

AI summary

A method and system for generating voltage and/or current oscillations in a single magnetic layer is provided. The method comprises applying a direct voltage/current to the layer in a longitudinal direction; and developing a longitudinal voltage between a pair of longitudinal voltage leads and/or a transverse voltage between a pair of transverse voltage leads. The magnetic layer comprises a ferrimagnetic or antiferrimagnetic material having a first and second magnetic sub-lattice, wherein the first sub-lattice is a dominant sub-lattice such that the charge carriers at the Fermi energy originate predominantly from the dominant sub-lattice and the charge carriers at the Fermi energy are spin polarised. In some embodiments, the dominant current carrying sub-lattice may lack inversion symmetry.