MRAM Buffer Layer Structure for Stable Anti-Ferromagnetic Coupling
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Solution Overview
Problem
Existing magnetoresistive random access memory (MRAM) technologies face challenges in maintaining the stability and efficiency of magnetoresistive effect elements due to issues with crystal structure disturbances and anti-ferromagnetic coupling, leading to performance deterioration and increased manufacturing costs.
Innovation Solution
The magnetic memory device employs a three-layer buffer layer structure comprising nonmagnetic layers with specific crystal structures and elements like silicon and germanium to stabilize the crystal structure of the shift cancelling layer, reducing disturbances and maintaining anti-ferromagnetic coupling, while also reducing the number of layers to lower manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional buffer layer structure is used, then manufacturing is simpler, but crystal structure disturbances occur and anti-ferromagnetic coupling deteriorates
Solution Approach 1:
The buffer layer is divided into three distinct sub-layers (first, second, and third nonmagnetic layers) with different crystal structures. This segmentation allows each sub-layer to perform a specific function: the first sub-layer provides a template for epitaxial growth, the second sub-layer suppresses unwanted crystal growth, and the third sub-layer stabilizes the overall structure. This resolves the contradiction by achieving reliable anti-ferromagnetic coupling through structured segmentation while maintaining controlled complexity.
Solution Approach 2:
The buffer layer employs a composite structure combining three different nonmagnetic materials with distinct crystal structures (face-centered cubic, body-centered cubic, and hexagonal close-packed). This composite approach leverages the unique properties of each material to collectively stabilize the shift cancelling layer's crystal structure and maintain anti-ferromagnetic coupling, resolving the contradiction between reliability and complexity.
2Stability of the object's composition
If the number of buffer layer layers is increased, then crystal structure stability improves, but manufacturing cost increases
Solution Approach 1:
Each sub-layer of the buffer layer is assigned a specific local function based on its crystal structure and material properties. The first sub-layer (face-centered cubic) provides epitaxial growth template, the second sub-layer (body-centered cubic) suppresses unwanted crystal growth, and the third sub-layer (hexagonal close-packed) stabilizes the structure. This local quality differentiation achieves crystal structure stability with exactly three layers, avoiding the need for additional layers and reducing manufacturing cost.
Solution Approach 2:
The invention changes the crystal structure parameter of each buffer layer sub-layer to optimize performance. By selecting materials with specific crystal structures (FCC, BCC, HCP) for each sub-layer, the invention achieves optimal crystal structure stability and anti-ferromagnetic coupling with a three-layer configuration, avoiding the need for more layers and thus reducing manufacturing complexity and cost.
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 enhances the magnetoresistance ratio and suppresses performance deterioration, achieving improved stability and cost-effectiveness in magnetoresistive effect elements.
Implementation Method 1
A magnetoresistive random access memory (MRAM) using a magnetoresistive effect element as a memory element is known
Data Source
AI summary
According to one embodiment, a magnetic memory device includes a magnetoresistive effect element. The magnetoresistive effect element includes a first ferromagnetic layer, a second ferromagnetic layer, a third ferromagnetic layer, a first nonmagnetic layer provided between the first ferromagnetic layer and the second ferromagnetic layer, a second nonmagnetic layer provided between the second ferromagnetic layer and the third ferromagnetic layer, a third nonmagnetic layer containing at least one element selected from Ir, Pt, Au, Rh, Pd, Ag, Ni, and Cu, a fourth nonmagnetic layer containing at least one element selected from Ta, W, Nb, Mo, V, and Cr, and a fifth nonmagnetic layer containing at least one element of Si and Ge.