Al Alloy Nonmagnetic Spacer Layer for Magnetoresistive Element Crystallinity
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Solution Overview
Problem
The magnetoresistive effect elements with large lattice mismatch between ferromagnetic and nonmagnetic layers face difficulties in improving crystallinity, which limits their magnetoresistance effect.
Innovation Solution
A magnetoresistive effect element is designed with a nonmagnetic spacer layer comprising an Al alloy (AlγX1-γ) and Heusler alloys for the ferromagnetic layers, where X is selected from specific elements and γ is between 0.5 and 1, reducing lattice mismatch and enhancing crystallinity, and the layers are stacked with a face-centered cubic lattice structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the nonmagnetic spacer layer is formed of pure Al, then the material is simple and easy to manufacture, but the lattice mismatch with ferromagnetic layers is large which deteriorates crystallinity
Solution Approach 1:
The patent applies composite materials by forming the nonmagnetic spacer layer using an Al alloy instead of pure Al. The Al alloy contains Al as the main component along with other elements that reduce lattice mismatch with ferromagnetic layers, thereby improving crystallinity while maintaining ease of manufacture through sputtering deposition
Solution Approach 2:
The patent applies parameter changes by modifying the composition parameters of the nonmagnetic spacer layer. By controlling the alloying elements and their concentrations in the Al alloy, the lattice constant is adjusted to reduce lattice mismatch with ferromagnetic layers, thereby improving crystallinity without significantly complicating the manufacturing process
2Device complexity
If the lattice mismatch between ferromagnetic layer and nonmagnetic spacer layer is large, then the structure is simple, but the crystallinity of these layers cannot be improved which deteriorates the magnetoresistance effect
Solution Approach 1:
The patent uses composite materials by employing an Al alloy with specific composition in the nonmagnetic spacer layer. This composite approach allows tuning of the lattice constant to match ferromagnetic layers better, improving crystallinity while keeping the overall structure relatively simple with just a layered configuration
Solution Approach 2:
The patent applies parameter changes by adjusting the compositional parameters of the Al alloy to optimize the lattice constant. This enables better lattice matching with ferromagnetic layers, improving crystallinity without significantly increasing structural complexity
3Manufacturing precision
If the nonmagnetic spacer layer uses Al alloy, then the lattice mismatch with ferromagnetic layers is reduced improving crystallinity, but the material composition becomes more complex
Solution Approach 1:
The patent applies composite materials by using an Al alloy with controlled composition in the nonmagnetic spacer layer. The alloying elements are selected and controlled to reduce lattice mismatch with ferromagnetic layers, improving crystallinity. The complexity of material composition is managed by focusing on specific alloying elements with controlled concentrations rather than multiple uncontrolled components
4Device complexity
If pure Al is used for nonmagnetic spacer layer, then the material is simple, but the magnetoresistance effect is insufficient due to poor crystallinity
Solution Approach 1:
The patent applies composite materials by replacing pure Al with an Al alloy in the nonmagnetic spacer layer. The alloy composition is designed to reduce lattice mismatch with ferromagnetic layers, improving crystallinity and thereby enhancing the magnetoresistance effect. The increased reliability in magnetoresistance performance justifies the slight increase in material complexity
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 improves the crystallinity of both the ferromagnetic and nonmagnetic layers, resulting in a significant increase in the magnetoresistive effect, as evidenced by higher normalized MR ratios and reduced spin scattering.
Implementation Method 1
the magnetoresistive effect element includes: a first ferromagnetic layer as a magnetization fixed layer; a second ferromagnetic layer as a magnetization free layer; and a nonmagnetic spacer layer provided between the first ferromagnetic layer and the second ferromagnetic layer
Data Source
AI summary
A magnetoresistive effect element according to the present invention includes: a first ferromagnetic layer as a magnetization fixed layer; a second ferromagnetic layer as a magnetization free layer; and a nonmagnetic spacer layer provided between the first ferromagnetic layer and the second ferromagnetic layer. The nonmagnetic spacer layer comprises an Al alloy represented by General Formula (1), and thereby lattice mismatch between the nonmagnetic spacer layer and the first ferromagnetic layer and/or the second ferromagnetic layer is reduced, compared to lattice mismatch when the nonmagnetic spacer layer is formed of Al.AlγX1-γ (1)[wherein, X indicates one element selected from the group consisting of Li, N, Mg, Si, Sc, Cr, Fe, Ni, Cu, Zn, Ga, Ge, Zr, Ru, Pd, Ag, Sn, W, Pt, Au and Th, and γ is 0.5<γ<1.]