Topological Insulator Magnetic Sensor with Exchange Coupler

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Solution Overview

Problem

Magnetic sensors using topological insulators face challenges in sensitivity, overall performance, and scalability due to the large magnetic field required to break time reversal symmetry, typically in the range of 20 Tesla, and complex fabrication processes.

Innovation Solution

A magnetic sensor design incorporating a thin-film topological insulator with an insulating magnetic coupler that amplifies the applied magnetic field through a magnetic exchange effect, allowing the sensor to respond to smaller magnetic fields and enhancing sensitivity and scalability, while maintaining operation over a broad temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If topological insulator material is used as the active sensing component, then the sensor can operate at room temperature with broad temperature range, but the magnetic field required to break time reversal symmetry is relatively large (approximately 20 Tesla)

Engineering Contradiction:

Improveoperating temperature rangeVSAvoidmagnetic field strength required

Core Design Contradiction:

TemperatureVSDifficulty of detecting and measuring

Solution Approach 1:

A magnetic coupler layer is introduced as an intermediary component between the external magnetic field source and the topological insulator sensing element. This magnetic coupler amplifies the applied magnetic field through magnetic exchange coupling, enabling the topological insulator to respond to smaller external magnetic fields while maintaining its room temperature operation capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The sensor employs a composite structure combining topological insulator material with magnetic coupler materials. This composite approach leverages the unique properties of both materials: the topological insulator provides room temperature operation and the magnetic coupler provides field amplification, together resolving the contradiction between temperature range and magnetic field strength requirements

Inventive Principle:

Principle #40Composite materials

2Measurement precision

If conventional magnetic sensing components are used, then sensitivity can be achieved, but the fabrication processes are complex and scalability is limited

Engineering Contradiction:

ImprovesensitivityVSAvoidfabrication process complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The invention changes the material parameters by using topological insulator materials with specific electronic band structure properties (insulating bulk with conducting surface states). This material parameter change enables simplified fabrication processes while maintaining high sensitivity, as the topological protection of surface states provides robust sensing capability without requiring complex fabrication sequences

Inventive Principle:

Principle #35Parameter changes

3Reliability

If larger magnetic fields are applied to break time reversal symmetry, then the sensing response can be achieved, but the power requirements and operational constraints increase

Engineering Contradiction:

Improvesensing responseVSAvoidpower requirements

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The magnetic coupler acts as an intermediary that concentrates and amplifies the magnetic field at the topological insulator interface. This allows reliable sensing response to be achieved with smaller external magnetic fields, thereby reducing power requirements and operational constraints while maintaining sensing reliability

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 sensor achieves increased sensitivity and scalability, operating effectively from 0.10 Tesla to 20 Tesla and maintaining performance from absolute zero to 250 degrees Celsius, with low-power requirements and no intrinsic size limitations.

Implementation Method 1

an insulating magnetic coupler that amplifies the applied magnetic field through a magnetic exchange effect

Methodology Applied

Scientific EffectMagnetic exchange effect:

Implementation Method 2

In the presence of a sufficiently strong applied perpendicular magnetic field, time-reversal symmetry is broken and an energy gap emerges for these surface states, which results in a change in the resistance of the topological insulator material in response to the magnetic field

Methodology Applied

Scientific EffectTime reversal symmetry breaking:

Implementation Method 3

topological insulators demonstrate a non-saturating linear response to large magnetic fields due to weak anti-localization arising from strong spin-orbit coupling

Methodology Applied

Scientific EffectWeak anti-localization:

Data Source

PatentUS10170688B2Magnetic field sensor based on topological insulator and insulating coupler materials

Publication Date: 2019.01.01 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Embodiments are directed to a sensor having a first electrode, a second electrode and a detector region electrically coupled between the first electrode region and the second electrode region. The detector region includes a first layer having a topological insulator. The topological insulator includes a conducting path along a surface of the topological insulator, and the detector region further includes a second layer having a first insulating magnetic coupler, wherein a magnetic field applied to the detector region changes a resistance of the conducting path.