Heusler MR Element Structure for Higher Sensor Output
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Solution Overview
Problem
Existing magnetoresistance effect elements with Heusler alloys face challenges in achieving a large MR ratio due to amorphous ferromagnetic layers, which hinder effective signal output.
Innovation Solution
Incorporating a crystallized Co-based Heusler alloy with specific additive elements in the ferromagnetic layers, along with a boron-absorbing layer and lattice-matched structures, to enhance crystallinity and spin polarization, thereby increasing the MR ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Heusler alloy is used for the ferromagnetic layer to increase spin polarization, then the output signal of the magnetic sensor is expected to increase, but the Heusler alloy is difficult to crystallize unless formed on a thick base substrate having high temperature or predetermined crystallinity, which causes a decrease in output
Solution Approach 1:
The ferromagnetic layer is divided into two distinct layers: a first layer containing the Co-based Heusler alloy and a second layer containing ferromagnetic element + boron + additive element. This segmentation allows the Heusler alloy to provide high spin polarization while the second layer facilitates crystallization, resolving the contradiction between achieving high output signal and ease of manufacture.
Solution Approach 2:
The invention uses a composite structure combining Co-based Heusler alloy with a ferromagnetic element-boron-additive element layer. This composite material approach enables the system to benefit from both the high spin polarization of the Heusler alloy and the crystallization capability of the ferromagnetic element-boron compound, thereby achieving both high output signal and manufacturability.
2Ease of manufacture
If the ferromagnetic layer is made amorphous to simplify manufacturing, then the fabrication process is easier, but a sufficiently large MR ratio cannot be obtained
Solution Approach 1:
By dividing the ferromagnetic layer into two layers with different functions, the first layer (Heusler alloy) can be formed with simpler amorphous or low-crystallinity structure for ease of manufacture, while the second layer (ferromagnetic element + boron + additive) is designed to crystallize and provide the necessary MR ratio, thus resolving the contradiction between fabrication simplicity and performance.
Solution Approach 2:
Different regions of the ferromagnetic layer structure are assigned different crystallinity qualities: the first layer near the non-magnetic layer can have lower crystallinity for ease of formation, while the second layer is engineered to achieve high crystallinity for optimal MR ratio, thereby resolving the contradiction through spatial differentiation of material properties.
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 proposed structure achieves a significant increase in the MR ratio, enabling improved signal output and performance in magnetic sensors and other applications.
Implementation Method 1
The Heusler alloy has high spin polarization and is expected to be able to increase the output signal of the magnetic sensor
Implementation Method 2
A magnetoresistance effect element is an element of which a resistance value in a lamination direction changes due to a magnetoresistance effect
Implementation Method 3
at least a part of the second layer is crystallized and the second layer contains a ferromagnetic element, elemental boron, and an additive element
Data Source
AI summary
A magnetoresistance effect element includes: a first ferromagnetic layer, a second ferromagnetic layer; and a non-magnetic layer provided between the first ferromagnetic layer and the second ferromagnetic layer, wherein at least one of the first ferromagnetic layer and the second ferromagnetic layer includes a first layer and a second layer in order from the side closer to the non-magnetic layer, the first layer contains a crystallized Co Heusler alloy, and at least a part of the second layer is crystallized and the second layer contains a ferromagnetic element and elemental boron.