Topological Insulator Magnetic Device RKKY Control

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Solution Overview

Problem

Conventional spin transfer torque (STT)-based devices require high voltage and current for switching, which is inefficient and difficult to integrate with CMOS logic devices, and existing methods for reducing current requirements are complex and require precise fabrication.

Innovation Solution

A magnetic solid state device is fabricated using a substrate with a topological insulator and perpendicular magnetic anisotropy (PMA) layers, where a gate contact controls Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between reference and free PMA bits to manage magnetic orientation with controlled voltages, allowing for low-power operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional STT-based devices use spin-polarized current injection to switch magnet orientation, then magnetic switching can be achieved, but high voltage and current are required which reduces energy efficiency

Engineering Contradiction:

Improveenergy efficiencyVSAvoidvoltage and current requirement

Core Design Contradiction:

Use of energy by moving objectVSPower

Solution Approach 1:

The patent introduces a topological insulator as an intermediary material between the substrate and the PMA layers. This topological insulator enables efficient spin-charge conversion through the spin Hall effect, allowing low-voltage operation. The topological insulator acts as a mediator that converts charge current into spin current with high efficiency, thereby reducing the direct current requirement for magnetic switching while maintaining effective magnet orientation control.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Use of energy by moving object

If voltage-induced changes in magnet easy axis orientation are used to reduce current requirement, then power efficiency improves, but precise fabrication is required to achieve nominal magnetic anisotropy

Engineering Contradiction:

Improvepower efficiencyVSAvoidfabrication precision

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent utilizes voltage-induced changes in the magnetic anisotropy energy (MAE) as a controllable parameter to switch between in-plane and out-of-plane magnetization states. By applying specific voltages that modify the MAE, the system can transition between different magnetic configurations without requiring precise fabrication of the magnetic layer thickness. This parameter control approach replaces fabrication precision requirements with electrical control, thereby reducing manufacturing complexity while maintaining power efficiency.

Inventive Principle:

Principle #35Parameter changes

3Power

If giant spin Hall effect is utilized to switch nanomagnets with current parallel to surface, then low-voltage operation is achieved with greater than unity spin injection efficiency, but device structure becomes more complex

Engineering Contradiction:

Improvevoltage operation levelVSAvoiddevice structure

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent employs a composite structure consisting of a topological insulator layer combined with perpendicular magnetic anisotropy (PMA) layers. This composite material system leverages the unique properties of topological insulators (high spin Hall angle) together with PMA layers to achieve low-voltage switching. The combination of these materials creates a synergistic effect where the topological insulator provides efficient spin-charge conversion while the PMA layers provide stable magnetic states, achieving low-power operation without excessive structural complexity.

Inventive Principle:

Principle #40Composite materials

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 solution enables low-power switching and non-volatile magnetic memory and logic operations, reducing the complexity of voltage-induced changes and improving integration with CMOS logic devices.

Implementation Method 1

the giant spin Hall effect in metals has been utilized to switch nanomagnets, which allows for low-voltage operation and greater than unity effective spin injection efficiencies

Methodology Applied

Scientific EffectSpin Hall Effect: Hall Effect

Implementation Method 2

A gate contact is utilized to receive various predetermined voltages for controlling the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between the reference PMA layer in the first PMA bit and the free PMA layer in the second PMA bit

Methodology Applied

Scientific EffectRKKY interaction:

Implementation Method 3

a first perpendicular magnetic anisotropy (PMA) bit having a reference PMA layer located on the topological insulator, and a second PMA bit having a free PMA layer located on, the topological insulator

Methodology Applied

Scientific EffectMagnetic Anisotropy: Anisotropy

Data Source

PatentUS20180323370A1Method for fabricating magnetic solid state devices

Publication Date: 2018.11.08 BOARD OF RGT THE UNIV OF TEXAS SYST

AI summary

A magnetic solid state device is disclosed. The magnetic solid state device includes a substrate and a topological insulator deposited on top of the substrate. The magnetic solid state device also includes a first perpendicular magnetic anisotropy (PMA) bit having a reference PMA layer located on the topological insulator, and a second PMA bit having a free PMA layer located on the topological insulator. A gate contact is utilized to receive various predetermined voltages for controlling the Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between the reference PMA layer in the first PMA bit and the free PMA layer in the second PMA bit.