MnGa-N Perpendicular Magnetic Layer for High Anisotropy and Flatness
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Solution Overview
Problem
Existing perpendicular magnetic materials face challenges in achieving high magnetic anisotropy energy density, low magnetic damping, and flatness necessary for high-density magnetic storage and memory devices, particularly in magnetic tunnel junctions, due to issues with noble metal costs and material formation difficulties.
Innovation Solution
A MnGa alloy with a small nitrogen content is used to form a perpendicular magnetic layer with a D022 or L10 crystal structure, achieving high magnetic anisotropy energy density and flatness through a reactive sputtering method, and incorporating germanium instead of gallium to maintain these properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If cobalt-based alloy materials or L10-type iron-platinum alloy are used as perpendicular magnetic layers, then high magnetic anisotropy energy density is achieved, but cost increases due to noble metal content and magnetic damping increases
Solution Approach 1:
The patent replaces expensive noble metal-based perpendicular magnetic materials (Co-Pt-Cr alloy, L10-type FePt alloy) with a manganese-gallium-nitrogen alloy that does not contain noble metals. This substitution significantly reduces material cost while maintaining the necessary magnetic properties for high-density recording applications.
Solution Approach 2:
The patent introduces nitrogen into the manganese-gallium alloy to form a Mn-Ga-N compound with a specific composition ratio (0 < x ≤ 0.5 in (Mn1-xMx)Ny). This compositional parameter change enables the material to achieve both high magnetic anisotropy energy density and low magnetic damping, resolving the contradiction between these two properties.
2Loss of energy
If manganese-gallium alloy is used as perpendicular magnetic layer, then magnetic damping is reduced and noble metals are eliminated, but layer flatness deteriorates making it difficult to form high-quality magnetic recording medium
Solution Approach 1:
The patent introduces nitrogen into the manganese-gallium alloy to form Mn-Ga-N compound with controlled composition (0 < x ≤ 0.5). This compositional modification fundamentally changes the material's properties, enabling it to form flat layers with high manufacturing precision while maintaining low magnetic damping and eliminating noble metals.
Solution Approach 2:
The patent creates a composite Mn-Ga-N alloy material that combines manganese, gallium, and nitrogen in specific proportions. This composite material exhibits superior properties compared to simple Mn-Ga alloy, achieving both flat layer formation and low magnetic damping simultaneously.
3Manufacturing precision
If homogeneous manganese-gallium-nitrogen layer with cubic system structure is formed by introducing nitrogen, then very flat layer is obtained, but magnetic anisotropy energy density decreases to a fraction of D022-type MnGa alloy
Solution Approach 1:
The patent carefully controls the nitrogen content and composition ratio (0 < x ≤ 0.5 in (Mn1-xMx)Ny) to prevent formation of the cubic E21-type Mn3GaN structure. By maintaining this specific compositional range, the material forms a tetragonal D022-type structure that simultaneously achieves flat layer morphology and high magnetic anisotropy energy density, avoiding the trade-off present in highly nitrogenated cubic structures.
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 approach results in a perpendicular magnetic layer with high magnetic anisotropy energy density, low saturation magnetization, and improved flatness, suitable for high-density magnetic recording and reduced power consumption in magnetic tunnel junctions.
Implementation Method 1
a perpendicular magnetic layer may be formed using this layer by a reactive sputtering method
Data Source
AI summary
Embodiments of the inventive concepts provide a flat perpendicular magnetic layer having a low saturation magnetization and a perpendicular magnetization-type tunnel magnetoresistive element using the same. The perpendicular magnetic layer is a nitrogen-poor (Mn1−xGax)Ny layer (0<x≤0.5 and 0<y<0.1) formed by providing nitrogen (N) into a MnGa alloy while adjusting a nitrogen amount. The perpendicular magnetic layer can be formed flat.