Thermoelectric Conversion Element With Spin Injection Layer

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Solution Overview

Problem

Current thermoelectric conversion elements using the spin-Seebeck and inverse spin-Hall effects face limitations in achieving high spin injection efficiency, which is crucial for generating large output power.

Innovation Solution

Incorporating a spin injection layer with a magnetic moment per unit volume smaller than the magnetic layer, magnetically coupled to both the magnetic and electromotive layers, to enhance spin injection efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a magnetic layer with high magnetic moment is used to generate spin-current, then the spin-current generation capability is improved, but the spin injection efficiency deteriorates

Engineering Contradiction:

Improvespin-current generation capabilityVSAvoidspin injection efficiency

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

A spin injection layer is introduced as an intermediary between the magnetic layer and the electromotive layer. This intermediate layer has a magnetic moment per unit volume smaller than the magnetic layer, serving as a buffer that improves spin injection efficiency while allowing the high magnetic moment magnetic layer to maintain its spin-current generation capability

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The magnetic moment per unit volume is varied across different layers: the spin injection layer has a smaller magnetic moment than the magnetic layer, creating an optimal gradient for spin current injection. This parameter optimization resolves the contradiction between high spin-current generation and high spin injection efficiency

Inventive Principle:

Principle #35Parameter changes

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 significantly improves spin injection efficiency, leading to a higher output power and more efficient thermoelectric conversion.

Implementation Method 1

The spin-Seebeck effect is a phenomenon in which when a temperature gradient is applied to the magnetic material, the spin-current is induced in a direction parallel to the temperature gradient

Methodology Applied

Scientific Effectspin-Seebeck effect:

Implementation Method 2

a phenomenon in which when the spin-current flows, an electromotive force is generated is known. This is called 'inverse spin-Hall effect'

Methodology Applied

Scientific Effectinverse spin-Hall effect:

Data Source

PatentUS9306153B2Thermoelectric conversion element and method for manufacturing the same

Publication Date: 2016.04.05 NEC CORP

AI summary

A thermoelectric conversion element includes a magnetic layer which has a component magnetized in an in-plane direction, an electromotive layer which includes a material with spin orbit coupling, and a spin injection layer. The spin injection layer is provided between the magnetic layer and the electromotive layer and magnetically coupled to both the magnetic layer and the electromotive layer. A magnetic moment per unit volume of the spin injection layer is smaller than the magnetic moment per unit volume of the magnetic layer.