Heusler Magnetoresistance Element for Low-Temperature Crystallization
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Solution Overview
Problem
Existing magnetoresistance effect elements using Heusler alloys struggle to achieve a large magnetoresistance change rate (MR ratio) due to the difficulty in crystallizing Heusler alloys without high-temperature film formation or thick underlying substrates.
Innovation Solution
A magnetoresistance effect element is designed with a first ferromagnetic layer comprising a Heusler alloy with partially crystallized Co, and a second ferromagnetic layer with a different ferromagnetic material, both containing specific atoms to promote crystallization and lattice matching, thereby enhancing the MR ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If high-temperature film formation or thick underlying substrate is used, then Heusler alloy crystallization is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
An amorphous alloy layer is introduced as an intermediary between the substrate and the Heusler alloy layer. This amorphous layer serves as a mediator that enables the Heusler alloy to crystallize at lower temperatures without requiring complex high-temperature processes or thick substrates, thus resolving the contradiction between achieving crystallinity and simplifying manufacturing
Solution Approach 2:
The invention changes the temperature parameter for film formation from high temperature to low temperature by using the amorphous alloy layer as a base. This parameter change allows the Heusler alloy to crystallize effectively without requiring high-temperature processing, thereby reducing manufacturing complexity while maintaining crystallinity
2Stability of the object's composition
If high-temperature film formation is used, then Heusler alloy crystallization is promoted, but output signal decreases
Solution Approach 1:
The invention changes the temperature parameter from high to low by using an amorphous alloy layer as a crystallization promoter. This allows the Heusler alloy to achieve sufficient crystallinity for high spin polarization without high-temperature processing, thereby maintaining large output signals while achieving the desired crystalline structure
3Ease of manufacture
If amorphous ferromagnetic layer is used, then manufacturing is simplified, but MR ratio is insufficient
Solution Approach 1:
The ferromagnetic layer is segmented into two distinct layers: an amorphous alloy layer and a Heusler alloy layer. The amorphous layer provides ease of manufacture and serves as a substrate for crystallization, while the Heusler alloy layer provides the necessary crystalline structure for high MR ratio, thus combining the advantages of both approaches
Solution Approach 2:
The invention uses a composite structure consisting of an amorphous alloy layer and a Heusler alloy layer. This composite material approach allows the bottom layer to be easily manufactured in amorphous form while the top layer achieves high crystallinity, thereby achieving both ease of manufacture and high MR ratio
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 magnetoresistance effect element achieves a large MR ratio without the need for high-temperature film formation or thick substrates, facilitating easier crystallization of Heusler alloys and improving the element's performance.
Implementation Method 1
The first layer has a Heusler alloy containing at least partially crystallized Co. The first layer and the second layer have added first atoms.
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.
Data Source
AI summary
A magnetoresistance effect element having a large MR ratio is provided.This magnetoresistance effect element includes: a first ferromagnetic layer; a second ferromagnetic layer; and a nonmagnetic layer. The first ferromagnetic layer includes a first layer and a second layer. The first layer is closer to the nonmagnetic layer than the second layer. The first layer has a Heusler alloy containing at least partially crystallized Co. The second layer contains a material different from the Heusler alloy and has at least a partially crystallized ferromagnetic material. The first layer and the second layer have added first atoms. The first atom is any one selected from the group consisting of Mg, Al, Cr, Mn, Ni, Cu, Zn, Pd, Cd, In, Sn, Sb, Pt, Au, and Bi.